|
The real $M@ wrote: Any explanation would be welcome.
Short Version: decimal numbers <> binary numbers
Longer Version: Wikipedia page on floating point numbers
This is a common type of problem that is well known and documented all over the web. In your case, you may be able to iterate from 0 to 1000 instead and divide by 10 inside the loop.
|
|
|
|
|
Computers represent everything in binary, not decimal, and everything has to be crammed into 32, 64, or 128 bits (Depending on the precision).
In binary, the digits after the decimal correspond to 1/2, 1/4, 1/8, 1/16, etc., instead of 1/10, 1/100, 1/1000.
So representing 0.3 in binary is kind of like, say, representing 10/3 or 22/7 in decimal... You can write it out to a lot of digits, but you can't get it exactly right in that form. Normally, this approximation gets hidden, but when you do arithmetic, these errors get compounded until it starts to become visible.
There are thousands of articles on the web about this... Here's one: http://docs.sun.com/source/806-3568/ncg_goldberg.html[^]
|
|
|
|
|
Thanks for both answers. I understand now
The more you know the more you know how little you know, you know?
|
|
|
|
|
On the room form,include a combo box taht holds the room name. use check boxes to indicate if the room has a jacuzzi, private access, or fireplace. display the bed type and the room rates from the beds table
How to bind the checked property of a check box to a boolean data field
data looks like this
beds table
Doubles D 79.95 69.95
King K 105 95
Queen Q 95 85
rooms table
Forest K False False True
Garden K True True False
Library Q False True False
Ocean K False True True
Sun Room D False False False
so far I have this
'data tier
Imports System.Data
Public Class RoomsDataTier
' Module-level variables.
Private ARoomTableAdapter _
As CottagesDataSetTableAdapters.RoomsTableAdapter
Private ABedsTableAdapter _
As CottagesDataSetTableAdapters.BedsTableAdapter
Private ACottagesDataSet As CottagesDataSet
Public Sub New()
Try
' Instantiate the TableAdapters and DataSet.
ABedsTableAdapter = New _
CottagesDataSetTableAdapters.BedsTableAdapter()
ARoomTableAdapter = New _
CottagesDataSetTableAdapters.RoomsTableAdapter()
ACottagesDataSet = New CottagesDataSet
' Fill the DataSet.
ARoomTableAdapter.Fill(ACottagesDataSet.Rooms)
ABedsTableAdapter.Fill(ACottagesDataSet.Beds)
Catch ex As Exception
Throw ex
End Try
End Sub
Public Function GetDataSet() As CottagesDataSet
' Return the DataSet.
Return ACottagesDataSet
End Function
End Class
Imports System.Data
Public Class Rooms
' Module-level variables.
Private AroomsDataTier As RoomsDataTier
Private AcottagesDataSet As CottagesDataSet
Private RoomsBindingSource As BindingSource
Private BedsBindingSource As BindingSource
Private Sub StoreForm_Load(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles MyBase.Load
' Set up the data for the combo box and text boxes.
Try
AroomsDataTier = New RoomsDataTier
AcottagesDataSet = AroomsDataTier.GetDataSet
' Set up stores binding source.
RoomsBindingSource = New BindingSource
With RoomsBindingSource
.DataSource = AcottagesDataSet
.DataMember = "Rooms"
.Sort = "Room"
End With
' Bind the form controls.
With RoomComboBox()
.DataSource = RoomsBindingSource
.DisplayMember = "Room"
.ValueMember = "BedCode"
.DataBindings.Add("text", RoomsBindingSource, _
"Room", False, DataSourceUpdateMode.Never)
.SelectedIndex = -1
End With
' Set up the binding source.
BedsBindingSource = New BindingSource
With BedsBindingSource
.DataSource = AcottagesDataSet
.DataMember = "Beds"
End With
Catch ex As Exception
MessageBox.Show("Error: " & ex.Message)
End Try
End Sub
Private Sub RoomNameComboBox_SelectionChangeCommitted( _
ByVal sender As Object, ByVal e As System.EventArgs) _
Handles RoomComboBox.SelectionChangeCommitted
' Retrieve the sales information for the grid.
Dim RoomsString As String
Static GridInitializedBoolean As Boolean
' Retrieve the ID of the selected store.
RoomsString = RoomComboBox.SelectedValue.ToString
RoomCheckBox1.DataBindings.Add("CheckState", RoomsBindingSource, "MyColumn", False, DataSourceUpdateMode.OnPropertyChanged, DBNull.Value)
' Initialize the grid's binding.
If Not GridInitializedBoolean Then
' Bind and format the grid.
DataGridView1.DataSource = BedsBindingSource
GridInitializedBoolean = True
End If
' Filter the grid's data.
BedsBindingSource.Filter = "BedCode = '" & RoomsString & "'"
End Sub
end class
I am getting a runtime error saying that
Cannot bind to the property or column MyColumn on the DataSource. Parameter name: dataMember
|
|
|
|
|
This is just a guess but I think you're trying to bind the checkbox to a field in your data source named "MyColumn". Does your data source (which I believe comes from your database) have a column named "MyColumn"? If not, change "MyColumn" to the name of the field you want to bind to.
|
|
|
|
|
I changed the column name and changed but now it is saying same thing
Cannot bind to the property or column Jacuzzi on the DataSource. Parameter name: dataMember
|
|
|
|
|
Again I'm just speculating but what is the data type of Jacuzzi in you database? It would need to be a boolean type and not a string.
|
|
|
|
|
It is a boolean type true , false
|
|
|
|
|
I changed my code little bit
Private Sub RoomNameComboBox_SelectionChangeCommitted( _
ByVal sender As Object, ByVal e As System.EventArgs) _
Handles RoomComboBox.SelectionChangeCommitted
' Retrieve the sales information for the grid.
Dim RoomsString As String
Dim RoomDataRow As DataRow
Dim BedDataRow As DataRow
AroomsDataTier = New RoomsDataTier
AcottagesDataSet = AroomsDataTier.GetDataSet
RoomDataRow = AcottagesDataSet.Rooms.FindByRoom(RoomComboBox.SelectedValue.ToString)
BedDataRow = RoomDataRow.GetParentRow("BedsToRooms")
' Retrieve the ID of the selected store.
RoomsString = RoomComboBox.SelectedValue.ToString
CheckBox1.Checked = CBool(RoomDataRow!Jacuzzi)
CheckBox2.Checked = CBool(RoomDataRow!Private_Access)
CheckBox3.Checked = CBool(RoomDataRow!Fireplace)
TextBox1.Text = CDbl(BedDataRow!WeekdayRate).ToString("c")
TextBox2.Text = CDbl(BedDataRow!WeekendRate).ToString("C")
End Sub
now the error was
Object reference not set to an instance of an object.
|
|
|
|
|
Then you need to step through the code and find which object isn't being set correctly. My guess is that AcottagesDataSet.Rooms.FindByRoom(RoomComboBox.SelectedValue.ToString) isn't returning anything.
|
|
|
|
|
Dear All,
I have designed a JPG file and want to use in splash screen in my vb.net project. I have set this image in form's background image property. In this JPG file, the blank space is filled with white background by default. But I dont need to show this white background in splash screen. Someone told me that there is a way to do this job by using transparency key. I tried alot by setting form's transparency key to white and also form's back color to white, but it doesn't work. Can anyone help me...
Thanks
Ovais
|
|
|
|
|
The transparency key likely wont work for your image as the white is made of of several different shades of many colors. You probably would be best to just remove the white background from the jpg.Add an Alpha Channel to your image and clear out the white, if you don't have (or know you have) a program to do this, here are some instructions for doing it in GIMP which is a free editor.
http://weisbeek.freewebhostx.com/gimp/[^]
|
|
|
|
|
I'm not sure I'm right but JPEGs don't support transparency therefore try converting it to a PNG or GIF image and set the transparent colour in the colour pallet of the image.
Then set the image file as the background of the splash form and set the splash form transparency to the back color of the form.
Steve Jowett
-------------------------
Real programmers don't comment their code. If it was hard to write, it should be hard to read.
|
|
|
|
|
The image itself must support transparency, as has been said, you will have to save your image as a png or similar that supports transparency then make sure the transparent parts of the image really are transparent.
After that set the form transparency key and backColor to the same colour. I usually use Fuschia as it is to vile a colour to be used for real and instantly shows up if you made a mistake.
For more info on splash screens try any of the many articles here on code project eg. Creating a Splash Screen that runs without a message pump[^].
If you have knowledge, let others light their candles at it.
Margaret Fuller (1810 - 1850)
www.JacksonSoft.co.uk
|
|
|
|
|
You can theoretically draw the image with transparency because you can use the ImageAttributes class to draw an image with a color range that is transparent. As others have said, JPEG is a lossy format, and your area of pure white will be turned in to blocks of various similar shades of white by the algorithm, that's why a range of whites would be needed. As was also said, PNG supports an alpha channel, which means .NET can just draw it with a transparent area.
Christian Graus
Driven to the arms of OSX by Vista.
Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
|
|
|
|
|
Hi
I Create a Chart in WinForm But I Want to Create a Chart in Xtrareport With DataSource How I Use DataSource For Series in Xtrareport??
please send me a sample of Code
|
|
|
|
|
You should look for help in the Xtrareport documentation/forum...
|
|
|
|
|
You probably won't get a response to your question here.
Your bestter bet would be to ask in a forum dedicated to XtraReport, like the forums at DevExpress[^]. You know, the people who actually wrote XtraReport...
|
|
|
|
|
Hello please some body help me its urgent?
I m in trouble. While working on an VB6 application in Vss mode. i got system error. when i run this application captions of all buttons where gone. Can anybody help me? why this happens and how to get back the captions?
please Help??????????
|
|
|
|
|
VB6 - probably not, it is no longer a supported platform.
What is Vss mode?
I presume you are debugging the application not just running it from the exe.
I seem to remeber something like this happening, I have no idea how it was fixed, I'd close all other apps and try again, reboot if that does not work. I would get there is a problem between your app and windows.
|
|
|
|
|
VSS - Visual Source Safe.
And i had restart the system but problem not solved? m dont no? wat to do?
|
|
|
|
|
What is VSS mode? Are you referring to debugging the app inside the VB6 IDE ?
|
|
|
|
|
You should put VB6 in your subject, because it's been obsolete for so long, you'd need to work harder to attract people who still remember how they used to use it. Do you have the source code ? I assume so. Does the code set the text on the controls ? Have you tried running it on another machine ? It's either the case that your source code somehow lost all the text on the buttons ( in which case, you have source control to wind it back ), or something is broken on your computer, not your source code.
Christian Graus
Driven to the arms of OSX by Vista.
Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
|
|
|
|
|
Hi, I was wondering if anyone knew how to put your application into the msconfig startup folder using the registry. I tried using the following code but for some reason it isnt working for me. it will work when i debug, but when i publish the application it doesnt work.
Private Sub addstart()
registrykey = CreateObject("WScript.shell")
registrykey.RegWrite("HKEY_CURRENT_USER\SOFTWARE\MICROSOFT\WINDOWS\CURRENTVERSION\RUN\" & App, filepath)
End Sub
Private Sub removeStart()
On Error Resume Next
registrykey = CreateObject("WScript.shell")
registrykey.RegDelete("HKEY_CURRENT_USER\SOFTWARE\MICROSOFT\WINDOWS\CURRENTVERSION\RUN\PEM beta.exe")
End Sub
Is there a better way to do this?
Thanks
|
|
|
|
|
RyJaBy wrote: how to put your application into the msconfig startup folder
And just what do you mean by "msconfig startup folder"?? What do you mean by "it doesn't work"?
The Run key values are all command lines that execute only when a user logs in. The name/value pair you create in the Run key must have a unique name and its value must be a valid command line that would work just as if you copied it into the Start/Run box.
|
|
|
|