Introduction
Every time a customer loads your application, you have the opportunity to impress or disappoint with your splash screen. A good splash screen will:
- Run on a separate thread
- Fade in as it appears, and fade out as it disappears
- Display a running status message that is updated using a static method
- Display and update a predictive self-calibrating owner-drawn smooth-gradient progress bar
- Display the number of seconds remaining before load is complete
In this tutorial, we'll explore how to create a splash screen and add these features one at a time. We start with the creation of a simple splash screen, followed by the code changes required for the addition of each feature. You can skip to the bottom of the article to see the complete source code. I've also included a small test project in the download that demonstrates the splash screen.
Background
It was a lot of fun writing the code for this article and, while it's not perfect for all needs, I hope it saves you some coding time. The most fun for me is seeing a completely accurate and smoothly progressing progress bar as my application loads up. Please feel free to post any enhancement suggestions, bugs or other comments you may have.
Create the Simple Splash Screen Project
Start out by creating a Windows Forms project. Name it SplashScreen. Rename Form1.cs to SplashScreen.cs.
Now obtain a product bitmap with a light background suitable for putting text over. If you're lucky, a really talented person (like dzCepheus - see the thread below) will provide one for you. Set the Background Image property to it. Set the following properties on the form:
FormBorderStyle = None
StartPosition = CenterScreen
In the form constructor, add the line:
this.ClientSize = this.BackgroundImage.Size;
Go to the project properties and change the Output type to Class Library. At this point, if you are not adding this project to an existing solution, you may want to add another WinForms project to your solution for testing the splash screen. You can call the public methods from that class as you build the splash screen.
Make it Available from Static Methods
Because the splash screen will only need a single instance, you can simplify your code by using static methods to access it. By just referencing the SplashScreen project, a component can launch, update or close the splash screen without needing an object reference. Add the following code to SplashScreen.cs:
static SplashScreen ms_frmSplash = null;
static public void ShowForm()
{
ms_frmSplash = new SplashScreen();
Application.Run(ms_frmSplash);
}
static public void CloseForm()
{
ms_frmSplash.Close();
}
Put it on its Own Thread
A splash screen displays information about your application while it is loading and initializing its components. If you are going to display any dynamic information during that time, you should put it on a separate thread to prevent it from freezing when initialization is hogging the main thread.
Start by using the Threading namespace:
using System.Threading;
Declare a static variable to hold the thread:
static Thread ms_oThread = null;
Now add a method to create and launch the splash screen on its own thread. Wait before returning to ensure that the static methods aren't called before the form exists:
static public void ShowSplashScreen()
{
if( ms_frmSplash != null )
return;
ms_oThread = new Thread( new ThreadStart(SplashScreen.ShowForm));
ms_oThread.IsBackground = true;
ms_oThread.SetApartmentState(ApartmentState.STA);
ms_oThread.Start();
while (ms_frmSplash == null || ms_frmSplash.IsHandleCreated == false)
{
System.Threading.Thread.Sleep(TIMER_INTERVAL);
}
}
Now ShowForm() can be made private, since the form will now be shown using ShowSplashScreen().
static private void ShowForm()
Add Code to Fade In and Fade Out
It can add real flair to your splash screen by having it fade in when it first appears, and fade out just as your application appears. The form's Opacity property makes this easy.
Declare variables defining increment and decrement rate. These define how quickly the form appears and disappears. They are directly related to the timer interval, since they represent how much the Opacity increases or decreases per timer tick, so if you modify the timer interval, you will want to change these proportionally.
private double m_dblOpacityIncrement = .05;
private double m_dblOpacityDecrement = .08;
private const int TIMER_INTERVAL = 50;
Add a timer to the form, rename it to UpdateTimer then modify the constructor to start the timer and initialize the opacity to zero.
this.Opacity = .0;
UpdateTimer.Interval = TIMER_INTERVAL;
UpdateTimer.Start();
Modify the CloseForm() method to initiate the fade away process instead of closing the form.
static public void CloseForm()
{
if( ms_frmSplash != null )
{
ms_frmSplash.m_dblOpacityIncrement = -ms_frmSplash.m_dblOpacityDecrement;
}
ms_oThread = null; ms_frmSplash = null;
}
Add a Tick event handler to change the opacity as the form is fading in or fading out, and to close the splash screen form when the opacity reaches 0.
private void UpdateTimer_Tick(object sender, System.EventArgs e)
{
if( m_dblOpacityIncrement > 0 )
{
if( this.Opacity < 1 )
this.Opacity += m_dblOpacityIncrement;
}
else
{
if( this.Opacity > 0 )
this.Opacity += m_dblOpacityIncrement;
else
this.Close();
}
}
At this point, you have a splash screen that fades into view when you call the ShowSplashScreen() method and starts fading away when you call the CloseForm() method.
Add Code to Display a Status String
Now that the basic splash screen is complete, we can add status information to the form, so the user can tell that something's going on. To do this, we add the member variable m_sStatus to the form to store the status and a label lblStatus to display it. We then add an accessor method to set the variable and modify the timer tick method to update the label. In general, it is illegal to update a UI element across threads, so, for example, an attempt to update a label on the splash screen from the main application thread will cause an exception (as of .NET 2.0). This code avoids that problem by updating data only in the status and progress updates. The timer event (on the splash screen thread) is used to do the UI updates, based on the member variables that were changed during the updates.
private string m_sStatus;
...
static public void SetStatus(string newStatus)
{
if( ms_frmSplash == null )
return;
ms_frmSplash.m_sStatus = newStatus;
}
Now we modify the UpdateTimer_Tick method to update the label.
lblStatus.Text = m_sStatus;
Now Add a Progress Bar
There's no reason to use the standard WinForms progress bar here unless you really want that look. We'll make a gradient progress bar by painting our own Panel control. To do this, add a panel named pnlStatus to the form and set its BackColor to Transparent. In practice, you might want to derive your own control from the Panel if you expect to use it in more than one place. Here, we'll just paint it in response to the timer event.
Declare a variable to hold the percent completion value. It is a double with a value that will vary between 0 and 1 as the progress bar progresses. Also declare a rectangle to hold the current progress rectangle.
private double m_dblCompletionFraction = 0;
private Rectangle m_rProgress;
For now, add a public property for setting the current percent complete. Later, when we add the self-calibration feature, we'll eliminate the need for it.
static public double Progress
{
get
{
if( ms_frmSplash != null )
return ms_frmSplash.m_dblCompletionFraction;
return 1.0;
}
set
{
if( ms_frmSplash != null )
ms_frmSplash.m_dblCompletionFraction = value;
}
}
Now we modify the timer's Tick event handler to calculate the portion of the Panel we want to paint.
...
int width = (int)Math.Floor(pnlStatus.ClientRectangle.Width
* m_dblCompletionFraction);
int height = pnlStatus.ClientRectangle.Height;
int x = pnlStatus.ClientRectangle.X;
int y = pnlStatus.ClientRectangle.Y;
if( width > 0 && height > 0 )
{
m_rProgress = new Rectangle( x, y, width, height);
}
...
Now, still in the UpdateTimer_Tick event handler, paint the gradient progress bar. Start by adding the System.Drawing.Drawing2D namespace. You will probably want to fiddle with the RGB values to get a color scheme that works with your graphic.
using System.Drawing.Drawing2D;
if( e.ClipRectangle.Width > 0 && m_iActualTicks > 1 )
{
LinearGradientBrush brBackground =
new LinearGradientBrush(m_rProgress,
Color.FromArgb(50, 50, 200),
Color.FromArgb(150, 150, 255),
LinearGradientMode.Horizontal);
e.Graphics.FillRectangle(brBackground, m_rProgress);
}
}
Smooth the Progress by Extrapolating Between Progress Updates
I don't know about you, but I've always been annoyed by the way progress bars progress. They're jumpy, stop during long operations, and always cause me vague anxiety that maybe they've stopped responding.
Well, this next bit of code tries to alleviate that anxiety by making the progress bar move even during lengthy operations. We do this by changing the meaning of the Progress updates. Instead of indicating current percent complete, they now indicate the percentage of time we expect the current activity to take before the next Progress update. For example, the first update might indicate that 25% of the total will pass before the second update. This allows us to use the timer to paint more and more of the status bar, up to and including 25% (but not beyond) while we are waiting for the next update. For now, we'll guess at how much to progress per timer tick. Later, we'll calculate this based on experience.
Add member variables to represent the previous progress and the amount to increment the progress bar per timer tick.
private double m_dblLastCompletionFraction = 0.0;
private double m_dblPBIncrementPerTimerInterval = .015;
Modify the Progress property to save the previous value before setting the new Progress value.
ms_frmSplash.m_dblLastCompletionFraction =
ms_frmSplash.m_dblCompletionFraction;
Modify the Timer.Tick event handler to do the progressive update:
if( m_dblLastCompletionFraction < m_dblCompletionFraction )
{
m_dblLastCompletionFraction += m_dblPBIncrementPerTimerInterval;
int width = (int)Math.Floor(pnlStatus.ClientRectangle.Width
* m_dblLastCompletionFraction);
int height = pnlStatus.ClientRectangle.Height;
int x = pnlStatus.ClientRectangle.X;
int y = pnlStatus.ClientRectangle.Y;
if (width > 0 && height > 0) {
...
}
}
Now Make the Progress Bar Calibrate Itself
We can now eliminate the need to specify the progress percentages by calculating the values and remembering them between splash screen invocations. Notice that this will work only if you make a fixed sequence of calls to SetStatus() and SetReferencePoint() during startup.
XML Storage
You can use any persistent storage mechanism for remembering these values (there are only 2 strings to store) between invocations. Here, we'll use an XML file stored in a user-specific location that's writable even when a user is logged in with non-administrative privileges. (In an earlier version of this article, we used the windows registry.)
using System.Xml;
...
internal class SplashScreenXMLStorage
{
private static string ms_StoredValues = "SplashScreen.xml";
private static string ms_DefaultPercents = "";
private static string ms_DefaultIncrement = ".015";
static public string Percents
{
get { return GetValue("Percents", ms_DefaultPercents); }
set { SetValue("Percents", value); }
}
static public string Interval
{
get { return GetValue("Interval", ms_DefaultIncrement); }
set { SetValue("Interval", value); }
}
static private string StoragePath
{
get {return Path.Combine(Application.UserAppDataPath, ms_StoredValues);}
}
static private string GetValue(string name, string defaultValue)
{
if (!File.Exists(StoragePath))
return defaultValue;
try
{
XmlDocument docXML = new XmlDocument();
docXML.Load(StoragePath);
XmlElement elValue = docXML.DocumentElement.SelectSingleNode(name) as XmlElement;
return (elValue == null) ? defaultValue : elValue.InnerText;
}
catch
{
return defaultValue;
}
}
static public void SetValue(string name, string stringValue)
{
XmlDocument docXML = new XmlDocument();
XmlElement elRoot = null;
if (!File.Exists(StoragePath))
{
elRoot = docXML.CreateElement("root");
docXML.AppendChild(elRoot);
}
else
{
docXML.Load(StoragePath);
elRoot = docXML.DocumentElement;
}
XmlElement value = docXML.DocumentElement.SelectSingleNode(name) as XmlElement;
if (value == null)
{
value = docXML.CreateElement(name);
elRoot.AppendChild(value);
}
value.InnerText = stringValue;
docXML.Save(StoragePath);
}
}
Member Variables
Now declare variables for keeping track of how long each interval between updates is taking (this time) and what it took per interval last time (from the XML file). Declare some Boolean flags to indicate whether this is the first launch and the timer has been started.
private int m_iIndex = 1;
private int m_iActualTicks = 0;
private ArrayList m_alPreviousCompletionFraction;
private ArrayList m_alActualTimes = new ArrayList();
private DateTime m_dtStart;
private bool m_bFirstLaunch = false;
private bool m_bDTSet = false;
Reference Points
We need to declare methods for recording various reference points during application startup. Reference points are critical to making a self-calibrating progress bar since they replace progress bar percent-complete updates. (The percent complete for each reference point will be calculated from the prior invocation of the progress bar.) To make the best use of this capability, you should sprinkle reference points inside of the initialization code that runs during application startup. The more you place, the smoother and more accurate your progress bar will be. This is when static access really pays off, because you don't need a reference to SplashScreen to call them.
First, we'll need a simple utility function to return elapsed Milliseconds since the Splash Screen first appeared. This is used for calculating the percentage of overall time allocated to each interval between ReferencePoint calls.
private double ElapsedMilliSeconds()
{
TimeSpan ts = DateTime.Now - m_dtStart;
return ts.TotalMilliseconds;
}
Now we'll be modifying SetStatus() and adding a new SetReferencePoint() method. Both call SetReferenceInternal() which records the time of the first call and adds the elapsed time of each subsequent call to an array for later processing. It sets the progress bar values by referencing previous recorded values for the progress bar. For example, if we're processing the third SetReferencePoint() call, we use the actual percentage of the overall load time that occurred between the third and fourth calls during the previous invocation. First, add the SetReferencePoint() method and SetReferenceInternal() which does the work of recording the time taken since the splash screen was started.
static public void SetReferencePoint()
{
if( ms_frmSplash == null )
return;
ms_frmSplash.SetReferenceInternal();
}
private void SetReferenceInternal()
{
if (m_bDTSet == false)
{
m_bDTSet = true;
m_dtStart = DateTime.Now;
ReadIncrements();
}
double dblMilliseconds = ElapsedMilliSeconds();
m_alActualTimes.Add(dblMilliseconds);
m_dblLastCompletionFraction = m_dblCompletionFraction;
if (m_alPreviousCompletionFraction != null && m_iIndex < m_alPreviousCompletionFraction.Count)
m_dblCompletionFraction = (double)m_alPreviousCompletionFraction[m_iIndex++];
else
m_dblCompletionFraction = (m_iIndex > 0) ? 1 : 0;
}
The next two functions, ReadIncrements() and StoreIncrements(), read and write the calculated intervals associated with each of the ReferencePoint values.
private void ReadIncrements()
{
string sPBIncrementPerTimerInterval = SplashScreenXMLStorage.Interval;
double dblResult;
if (Double.TryParse(sPBIncrementPerTimerInterval,
System.Globalization.NumberStyles.Float,
System.Globalization.NumberFormatInfo.InvariantInfo, out dblResult) == true)
m_dblPBIncrementPerTimerInterval = dblResult;
else
m_dblPBIncrementPerTimerInterval = .0015;
string sPBPreviousPctComplete = SplashScreenXMLStorage.Percents;
if (sPBPreviousPctComplete != "")
{
string[] aTimes = sPBPreviousPctComplete.Split(null);
m_alPreviousCompletionFraction = new ArrayList();
for (int i = 0; i < aTimes.Length; i++)
{
double dblVal;
if (Double.TryParse(aTimes[i],System.Globalization.NumberStyles.Float,
System.Globalization.NumberFormatInfo.InvariantInfo, out dblVal))
m_alPreviousCompletionFraction.Add(dblVal);
else
m_alPreviousCompletionFraction.Add(1.0);
}
}
else
{
m_bFirstLaunch = true;
}
}
private void StoreIncrements()
{
string sPercent = "";
double dblElapsedMilliseconds = ElapsedMilliSeconds();
for (int i = 0; i < m_alActualTimes.Count; i++)
sPercent += ((double)m_alActualTimes[i] /
dblElapsedMilliseconds).ToString("0.####",
System.Globalization.NumberFormatInfo.InvariantInfo) + " ";
SplashScreenXMLStorage.Percents = sPercent;
m_dblPBIncrementPerTimerInterval = 1.0 / (double)m_iActualTicks;
SplashScreenXMLStorage.Interval =
m_dblPBIncrementPerTimerInterval.ToString("#.000000",
System.Globalization.NumberFormatInfo.InvariantInfo);
}
We now can modify the SetStatus() method to add a Reference when the Status is updated. We also add an overloaded method to permit a Status update without the SetReferenceInternal() call. This is useful if you are in a section of code that has a variable set of status string updates. Note that depending on how often SetStatus() is called, you may not need many SetReference() calls in your startup code.
static public void SetStatus(string newStatus)
{
SetStatus(newStatus, true);
}
static public void SetStatus(string newStatus, bool setReference)
{
if (ms_frmSplash == null)
return;
ms_frmSplash.m_sStatus = newStatus;
if (setReference)
ms_frmSplash.SetReferenceInternal();
}
We also need to modify the timer tick handler to paint only when m_bFirstLaunch is false. This prevents the first launch from showing an uncalibrated progress bar.
...
if(m_bFirstLaunch == false && m_dblLastCompletionFraction < m_dblCompletionFraction)
...
Add a Time Remaining Counter
Finally, we can fairly accurately estimate the remaining time for initialization by examining what percentage is yet to be done. Add a label called lblTimeRemaining to the splash screen form to display it. Add a member variable m_sTimeRemaining to hold the corresponding string, then add the following code to the UpdateTimer_Tick() event handler to update the lblTimeRemaining label on the SplashScreen form.
private string m_sTimeRemaining;
...
private void UpdateTimer_Tick(object sender, System.EventArgs e)
{
...
int iSecondsLeft = 1 + (int)(TIMER_INTERVAL * ((1.0 - m_dblLastCompletionFraction) / m_dblPBIncrementPerTimerInterval)) / 1000;
m_sTimeRemaining = (iSecondsLeft == 1) ? string.Format("1 second remaining") : string.Format("{0} seconds remaining", iSecondsLeft);
...
lblTimeRemaining.Text = m_sTimeRemaining;
}
Also modify the ReadIncrements() method which clears the time remaining label as follows:
private void ReadIncrements()
{
...
m_sTimeRemaining = "";
...
}
Note that the label is set using a member variable. This makes it possible to set the time remaining text across threads without causing a cross-thread exception.
Using the SplashScreen
To use the splash screen, just call SplashScreen.ShowSplashScreen() on the first line of your Main() entry point. Periodically call either SetStatus() (if you have a new status to report) or SplashScreen.SetReferencePoint() (if you don't) to calibrate the progress bar. When your initialization is complete, call SplashScreen.CloseForm() to start the fade out process. Take a look at the test module provided in the download if you have any questions.
You may want to play around with the various constants to adjust the time of fade in and fade out. If you set the interval to a very short time (like 10 ms), you'll get a beautiful smoothly progressing progress bar but your performance may suffer.
When the application first loads, you will notice that the progress bar and time remaining counter do not display. This is because the splash screen needs one load to calibrate the progress bar. It will appear on subsequent application launches.
SplashScreen.cs Source Code
using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.IO;
using System.Threading;
using System.Windows.Forms;
using System.Xml;
using Microsoft.Win32;
using System.Runtime.InteropServices;
namespace SplashScreen
{
public partial class SplashScreen : Form
{
#region Member Variables
private static SplashScreen ms_frmSplash = null;
private static Thread ms_oThread = null;
private double m_dblOpacityIncrement = .05;
private double m_dblOpacityDecrement = .08;
private const int TIMER_INTERVAL = 50;
private string m_sStatus;
private string m_sTimeRemaining;
private double m_dblCompletionFraction = 0.0;
private Rectangle m_rProgress;
private double m_dblLastCompletionFraction = 0.0;
private double m_dblPBIncrementPerTimerInterval = .015;
private int m_iIndex = 1;
private int m_iActualTicks = 0;
private ArrayList m_alPreviousCompletionFraction;
private ArrayList m_alActualTimes = new ArrayList();
private DateTime m_dtStart;
private bool m_bFirstLaunch = false;
private bool m_bDTSet = false;
#endregion Member Variables
public SplashScreen()
{
InitializeComponent();
this.Opacity = 0.0;
UpdateTimer.Interval = TIMER_INTERVAL;
UpdateTimer.Start();
this.ClientSize = this.BackgroundImage.Size;
}
#region Public Static Methods
static public void ShowSplashScreen()
{
if (ms_frmSplash != null)
return;
ms_oThread = new Thread(new ThreadStart(SplashScreen.ShowForm));
ms_oThread.IsBackground = true;
ms_oThread.SetApartmentState(ApartmentState.STA);
ms_oThread.Start();
while (ms_frmSplash == null || ms_frmSplash.IsHandleCreated == false)
{
System.Threading.Thread.Sleep(TIMER_INTERVAL);
}
}
static public void CloseForm()
{
if (ms_frmSplash != null && ms_frmSplash.IsDisposed == false)
{
ms_frmSplash.m_dblOpacityIncrement = -ms_frmSplash.m_dblOpacityDecrement;
}
ms_oThread = null; ms_frmSplash = null;
}
static public void SetStatus(string newStatus)
{
SetStatus(newStatus, true);
}
static public void SetStatus(string newStatus, bool setReference)
{
if (ms_frmSplash == null)
return;
ms_frmSplash.m_sStatus = newStatus;
if (setReference)
ms_frmSplash.SetReferenceInternal();
}
static public void SetReferencePoint()
{
if (ms_frmSplash == null)
return;
ms_frmSplash.SetReferenceInternal();
}
#endregion Public Static Methods
#region Private Methods
static private void ShowForm()
{
ms_frmSplash = new SplashScreen();
Application.Run(ms_frmSplash);
}
private void SetReferenceInternal()
{
if (m_bDTSet == false)
{
m_bDTSet = true;
m_dtStart = DateTime.Now;
ReadIncrements();
}
double dblMilliseconds = ElapsedMilliSeconds();
m_alActualTimes.Add(dblMilliseconds);
m_dblLastCompletionFraction = m_dblCompletionFraction;
if (m_alPreviousCompletionFraction != null && m_iIndex
< m_alPreviousCompletionFraction.Count )
m_dblCompletionFraction = (double)m_alPreviousCompletionFraction[m_iIndex++];
else
m_dblCompletionFraction = (m_iIndex > 0) ? 1 : 0;
}
private double ElapsedMilliSeconds()
{
TimeSpan ts = DateTime.Now - m_dtStart;
return ts.TotalMilliseconds;
}
private void ReadIncrements()
{
string sPBIncrementPerTimerInterval = SplashScreenXMLStorage.Interval;
double dblResult;
if (Double.TryParse(sPBIncrementPerTimerInterval,
System.Globalization.NumberStyles.Float,
System.Globalization.NumberFormatInfo.InvariantInfo, out dblResult) == true)
m_dblPBIncrementPerTimerInterval = dblResult;
else
m_dblPBIncrementPerTimerInterval = .0015;
string sPBPreviousPctComplete = SplashScreenXMLStorage.Percents;
if (sPBPreviousPctComplete != "")
{
string[] aTimes = sPBPreviousPctComplete.Split(null);
m_alPreviousCompletionFraction = new ArrayList();
for (int i = 0; i < aTimes.Length; i++)
{
double dblVal;
if (Double.TryParse(aTimes[i],
System.Globalization.NumberStyles.Float,
System.Globalization.NumberFormatInfo.InvariantInfo, out dblVal) == true)
m_alPreviousCompletionFraction.Add(dblVal);
else
m_alPreviousCompletionFraction.Add(1.0);
}
}
else
{
m_bFirstLaunch = true;
m_sTimeRemaining = "";
}
}
private void StoreIncrements()
{
string sPercent = "";
double dblElapsedMilliseconds = ElapsedMilliSeconds();
for (int i = 0; i < m_alActualTimes.Count; i++)
sPercent += ((double)m_alActualTimes[i] / dblElapsedMilliseconds)
.ToString("0.####", System.Globalization.NumberFormatInfo.InvariantInfo) + " ";
SplashScreenXMLStorage.Percents = sPercent;
m_dblPBIncrementPerTimerInterval = 1.0 / (double)m_iActualTicks;
SplashScreenXMLStorage.Interval = m_dblPBIncrementPerTimerInterval
.ToString("#.000000", System.Globalization.NumberFormatInfo.InvariantInfo);
}
public static SplashScreen GetSplashScreen()
{
return ms_frmSplash;
}
#endregion Private Methods
#region Event Handlers
private void UpdateTimer_Tick(object sender, System.EventArgs e)
{
lblStatus.Text = m_sStatus;
if (m_dblOpacityIncrement > 0) {
m_iActualTicks++;
if (this.Opacity < 1)
this.Opacity += m_dblOpacityIncrement;
}
else {
if (this.Opacity > 0)
this.Opacity += m_dblOpacityIncrement;
else
{
StoreIncrements();
UpdateTimer.Stop();
this.Close();
}
}
if (m_bFirstLaunch == false && m_dblLastCompletionFraction < m_dblCompletionFraction)
{
m_dblLastCompletionFraction += m_dblPBIncrementPerTimerInterval;
int width = (int)Math.Floor(pnlStatus.ClientRectangle.Width
* m_dblLastCompletionFraction);
int height = pnlStatus.ClientRectangle.Height;
int x = pnlStatus.ClientRectangle.X;
int y = pnlStatus.ClientRectangle.Y;
if (width > 0 && height > 0)
{
m_rProgress = new Rectangle(x, y, width, height);
if (!pnlStatus.IsDisposed)
{
Graphics g = pnlStatus.CreateGraphics();
LinearGradientBrush brBackground =
new LinearGradientBrush(m_rProgress,
Color.FromArgb(58, 96, 151),
Color.FromArgb(181, 237, 254),
LinearGradientMode.Horizontal);
g.FillRectangle(brBackground, m_rProgress);
g.Dispose();
}
int iSecondsLeft = 1 + (int)(TIMER_INTERVAL *
((1.0 - m_dblLastCompletionFraction) / m_dblPBIncrementPerTimerInterval)) / 1000;
m_sTimeRemaining = (iSecondsLeft == 1) ?
string.Format("1 second remaining") :
string.Format("{0} seconds remaining", iSecondsLeft);
}
}
lblTimeRemaining.Text = m_sTimeRemaining;
}
private void SplashScreen_DoubleClick(object sender, System.EventArgs e)
{
CloseForm();
}
#endregion Event Handlers
}
#region Auxiliary Classes
internal class SplashScreenXMLStorage
{
private static string ms_StoredValues = "SplashScreen.xml";
private static string ms_DefaultPercents = "";
private static string ms_DefaultIncrement = ".015";
static public string Percents
{
get { return GetValue("Percents", ms_DefaultPercents); }
set { SetValue("Percents", value); }
}
static public string Interval
{
get { return GetValue("Interval", ms_DefaultIncrement); }
set { SetValue("Interval", value); }
}
static private string StoragePath
{
get {return Path.Combine(Application.UserAppDataPath, ms_StoredValues);}
}
static private string GetValue(string name, string defaultValue)
{
if (!File.Exists(StoragePath))
return defaultValue;
try
{
XmlDocument docXML = new XmlDocument();
docXML.Load(StoragePath);
XmlElement elValue = docXML.DocumentElement.SelectSingleNode(name) as XmlElement;
return (elValue == null) ? defaultValue : elValue.InnerText;
}
catch
{
return defaultValue;
}
}
static public void SetValue(string name,
string stringValue)
{
XmlDocument docXML = new XmlDocument();
XmlElement elRoot = null;
if (!File.Exists(StoragePath))
{
elRoot = docXML.CreateElement("root");
docXML.AppendChild(elRoot);
}
else
{
docXML.Load(StoragePath);
elRoot = docXML.DocumentElement;
}
XmlElement value = docXML.DocumentElement.SelectSingleNode(name) as XmlElement;
if (value == null)
{
value = docXML.CreateElement(name);
elRoot.AppendChild(value);
}
value.InnerText = stringValue;
docXML.Save(StoragePath);
}
}
#endregion Auxiliary Classes
}
Update
This article was originally written over 10 years ago, when the current version of .NET was 1.1. Over time, readers have reported a number of defects and suggestions for workarounds (in the comments below) that haven't, until now, been incorporated into the article. However, a few years back Mahin Gupta was kind enough to update the source code with fixes and changes based on those comments and had provided a link to that source that many folks were downloading and using. This update takes from that source code and incorporates the changes into the text of the article, as well as updating the attached zip file containing the code.
I'd like to thank Mahin, as well as the many folks who posted bug reports and fixes below. Some of the changes included in this update are:
- Fixed cross threading oversight (
lblTimeRemaining label was being set directly.)
- Alternative storage to avoid the windows registry (Colin Stansfield, Lagrange)
- Delay updates until the splash screen thread is started (daws)
timer.Stop() before closing the form (kilroytrout)- Draw the progress bar during the timer tick event (kilroytrout, cbschuld)
- Remaining time accuracy improvements (Pacman69)
- Double click to dismiss splash screen fault (Natural_Demon)
I didn't implement one suggestion. A few of the comments pointed out focus problems when the splash screen closes (in MDI applications). The suggestion was to set the owner of the splash screen to the appropriate parent form as part of closing the window. I tried all the proposed fixes (I think) and couldn't find something that works. The problem appears to be that setting a form's owner invokes code on the owner (AddOwnedForm) which is not thread safe. So even if you do it during an invoke, the operation fails with a cross thread exception. The only 'fix' for this I could find online was to turn off the exception (ControlCheckForIllegalCrossThreadCalls = false;) during the operation. I decided that might not be wise. So either cross thread form ownership is not possible, or I can't figure it out. Any suggestions for resolving this would be appreciated. In the test project, I found that calling this.Activate() before calling SplashScreen.CloseForm() was sufficient.
History
- 11-16-2003 First Version.
- 11-18-2003 Corrected some typos and clarified behavior when the application is first called. Changed code to not display the progress bar on the first load.
- 11-20-2003 Added improvements and bug fixes based on Quentin Pouplard's comments (below).
- 12-23-2003 Added the graphic provided for us by dzCepheus (below).
- 7-28-2013 Reviewed suggestions and bug fixes provided in the comments section and updated accordingly.
