Re: 'System.NullReferenceException' inside an Array - C# Discussion Boards

S. Senthil Kumar10-May-05 0:06

10-May-05 0:06

I bet your RecivedDataEvent comes in through a non UI thread. You must not call AppendText or for that matter any method/property at all on the textbox from within that thread.

You need to call BeginInvoke or Invoke to marshal the call to the UI thread. Have a look at http://www.codeproject.com/useritems/begininvoke.asp[^]. It explains why you need to do that and also tells you how to use BeginInvoke.

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

Re: richText box uses to much CPU

Snowjim10-May-05 0:11

Snowjim

10-May-05 0:11

Yes i am using Invoke, i know that only the creating thread would be operating on the object/control.

I have no tested the plain textbox and its MUCH faster it semes like, but it also uses alot more CPU.

now its starts on 50% and it increase a little.

I will run more testst.

The problem with plain textbox simes to be that it is not using the \r\n propperly? insted it becomes a square??

Is there any setting for this? in richtextbox this works fine!

Best Regards
SnowJim

Re: richText box uses to much CPU

S. Senthil Kumar10-May-05 0:30

S. Senthil Kumar

10-May-05 0:30

You can try System.Environment.NewLine

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

Re: richText box uses to much CPU

S. Senthil Kumar10-May-05 0:35

S. Senthil Kumar

10-May-05 0:35

And did you try BeginInvoke instead of Invoke?

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

Re: richText box uses to much CPU

Snowjim10-May-05 2:32

Snowjim

10-May-05 2:32

BeginInvoke helpt alot! Thanks!

Re: richText box uses to much CPU

mav.northwind10-May-05 2:20

mav.northwind

10-May-05 2:20

The plain TextBox uses just \n as line separator, while the RichTextBox uses \r\n.

Regards,
mav

'System.NullReferenceException' inside an Array

Vinnepin9-May-05 22:52

Vinnepin

9-May-05 22:52

Hey guys,

I got a little problem with an Array i made.

Here is the code:

<br />
using System;<br />
using MTV3D65;<br />
<br />
namespace Template<br />
{<br />
<br />
	/// <summary><br />
	/// Summary description for Grass.<br />
	/// </summary><br />
	public class GrassFactory<br />
	{<br />
<br />
		const float LandScapeSize = 256 * 8;   //the size of the landscape<br />
		const float GrassNumber = 200;         //the number of grassmeshes on a tile<br />
		const float NumberOfTiles = 12; <br />
<br />
		private int i;<br />
		private int x;<br />
		private int y;<br />
		private GrassType[,,] Grass;<br />
		private TVMesh[] GrassMeshes = new TVMesh[4];  //number of mesh types (grass, busg, rock...)<br />
<br />
		<br />
		//These variables are used internally. Don't f*** with them. :)<br />
		private float CamTilePosX;<br />
		private float CamTilePosY;<br />
		private float Distance;<br />
		private float DistX;<br />
		private float DistZ;<br />
		private float TranspDistance;<br />
		private float Transparency;<br />
		private float OneTileSize;<br />
		private float Denominator;<br />
		private float Transp2;<br />
<br />
		TVGlobals Globals;<br />
		TVEngine TV;<br />
<br />
<br />
		public GrassFactory(TVLandscape Land, TVScene Scene)<br />
		{<br />
			Globals = new TVGlobals();<br />
			TV = new TVEngine();<br />
<br />
			float PosX;<br />
			float PosZ;<br />
			float MeshRandom;<br />
			Random random = new Random();<br />
			<br />
			GrassType[,,] Grass = new GrassType[(int)NumberOfTiles, (int)NumberOfTiles, (int)GrassNumber];<br />
			  <br />
			OneTileSize = LandScapeSize / NumberOfTiles;<br />
			  <br />
			GrassMeshes[0] = Scene.CreateBillboard(Globals.GetTex("Tree01"), 0, 0, 0, 8, 4, "", true);<br />
			GrassMeshes[1] = Scene.CreateBillboard(Globals.GetTex("Tree02"), 0, 0, 0, 5, 6, "", true);<br />
			GrassMeshes[2] = Scene.CreateBillboard(Globals.GetTex("Tree03"), 0, 0, 0, 4, 7, "", true);<br />
			GrassMeshes[3] = Scene.CreateBillboard(Globals.GetTex("Tree04"), 0, 0, 0, 3, 2, "", true);<br />
			GrassMeshes[0].SetCollisionEnable(false);<br />
			GrassMeshes[1].SetCollisionEnable(false);<br />
			GrassMeshes[2].SetCollisionEnable(false);<br />
			GrassMeshes[3].SetCollisionEnable(false);<br />
			  <br />
			for (y = 0; y < (NumberOfTiles - 1); y++) <br />
			{<br />
				for (x = 0; x < (NumberOfTiles - 1); x++) <br />
				{<br />
					//Grass[x, y, 0].MeshType = (int)GrassNumber;   //IMPORTANT: this holds the number of meshes on this tile!!!! I know it's ugly but it works.<br />
					for (i = 1; i < GrassNumber; i++) <br />
					{<br />
						TV.AddToLog("X:" + x + " Y:" + y + " i:" + i);<br />
<br />
						PosX = OneTileSize * x + (float)random.NextDouble() * OneTileSize;<br />
						PosZ = OneTileSize * y + (float)random.NextDouble() * OneTileSize;<br />
						MeshRandom = (float)random.NextDouble();<br />
						Grass[x, y, i].Position.x = PosX;<br />
						Grass[x, y, i].Position.y = Land.GetHeight(PosX, PosZ);<br />
						Grass[x, y, i].Position.z = PosZ;<br />
						Grass[x, y, i].ColorR = 0.9f;<br />
						Grass[x, y, i].ColorG = 0.9f;<br />
						Grass[x, y, i].ColorB = 0.8f;<br />
						Grass[x, y, i].Size = Globals.Vector((float)random.NextDouble() * 0.4f + 0.8f, (float)random.NextDouble() * 0.4f + 0.8f, (float)random.NextDouble() * 0.4f + 0.8f);<br />
			          <br />
						if (MeshRandom > 0.2) <br />
						{      //Type of mesh<br />
							Grass[x, y, i].MeshType = 0;<br />
						}<br />
						else if (MeshRandom > 0.15) <br />
						{<br />
							Grass[x, y, i].MeshType = 1;<br />
						}<br />
						else if (MeshRandom > 0.1) <br />
						{<br />
							Grass[x, y, i].MeshType = 2;<br />
						}<br />
						else<br />
						{<br />
							Grass[x, y, i].MeshType = 3;<br />
						}<br />
					}<br />
				}<br />
			}<br />
			  <br />
			TranspDistance = OneTileSize * 0.9f;  //this is the range of transparent area. 0.9999: the meshes pop up, 0:everything is transparent at least a bit<br />
			  <br />
			Denominator = 1 / ((OneTileSize * OneTileSize) - (TranspDistance * TranspDistance)); //needed for calculation speedup<br />
			Transp2 = TranspDistance * TranspDistance;   //needed for calculation speedup<br />
		}<br />
<br />
		public void Render(MTV3D65.TV_3DVECTOR CamPos)  //this tells what tiles should be rendered. Campos is the camera's position vector<br />
		{<br />
			GrassMeshes[0].Enable(true);<br />
			GrassMeshes[1].Enable(true);<br />
			GrassMeshes[2].Enable(true);<br />
			GrassMeshes[3].Enable(true);<br />
			CamTilePosX = (CamPos.x - OneTileSize / 2) / OneTileSize;<br />
			CamTilePosY = (CamPos.z - OneTileSize / 2) / OneTileSize;<br />
<br />
			DrawSurround(CamTilePosX, CamTilePosY, CamPos);<br />
<br />
			if (CamTilePosX - 1 >= 0 && CamTilePosY - 1 >= 0) <br />
				DrawSurround(CamTilePosX - 1, CamTilePosY - 1, CamPos);<br />
			<br />
			if (CamTilePosY - 1 >= 0) <br />
				DrawSurround( CamTilePosX, CamTilePosY - 1, CamPos);<br />
		<br />
			if (CamTilePosX + 1 < NumberOfTiles && CamTilePosY - 1 >= 0) <br />
				DrawSurround( CamTilePosX + 1, CamTilePosY - 1, CamPos);<br />
			<br />
			if (CamTilePosX - 1 >= 0 && CamTilePosY + 1 < NumberOfTiles) <br />
				DrawSurround( CamTilePosX - 1, CamTilePosY + 1, CamPos);<br />
			<br />
			if (CamTilePosY + 1 < NumberOfTiles) <br />
				DrawSurround( CamTilePosX, CamTilePosY + 1, CamPos);<br />
			<br />
			if (CamTilePosX + 1 < NumberOfTiles) <br />
				DrawSurround( CamTilePosX + 1, CamTilePosY, CamPos);<br />
			<br />
			if (CamTilePosX + 1 < NumberOfTiles && CamTilePosY + 1 < NumberOfTiles) <br />
				DrawSurround( CamTilePosX + 1, CamTilePosY + 1, CamPos);<br />
			<br />
			if (CamTilePosX - 1 >= 0) <br />
				DrawSurround( CamTilePosX - 1, CamTilePosY, CamPos);<br />
			<br />
			GrassMeshes[0].Enable(false);<br />
			GrassMeshes[1].Enable(false);<br />
			GrassMeshes[2].Enable(false);<br />
			GrassMeshes[3].Enable(false);<br />
		}<br />
		<br />
		private void DrawSurround(float x, float y, MTV3D65.TV_3DVECTOR CamPos)<br />
		{<br />
			for (i = 1; i < Grass[(int)x, (int)y, 0].MeshType; i++) <br />
			{<br />
				GrassMeshes[Grass[(int)x, (int)y, i].MeshType].SetPosition(Grass[(int)x, (int)y, i].Position.x, Grass[(int)x, (int)y, i].Position.y, Grass[(int)x, (int)y, i].Position.z);<br />
				GrassMeshes[Grass[(int)x, (int)y, i].MeshType].SetScale(Grass[(int)x, (int)y, i].Size.x, Grass[(int)x, (int)y, i].Size.y, Grass[(int)x, (int)y, i].Size.z);    //you may disable this line to gain a few (5-6) FPS<br />
				DistX = Grass[(int)x, (int)y, i].Position.x - CamPos.x;<br />
				DistZ = Grass[(int)x, (int)y, i].Position.z - CamPos.z;<br />
				Distance = (DistX * DistX + DistZ * DistZ);<br />
<br />
				if (Distance > Transp2) <br />
				{<br />
					Transparency = 1 - ((Distance - Transp2) * Denominator);<br />
					if (Transparency > 0) <br />
					{<br />
						GrassMeshes[Grass[(int)x, (int)y, i].MeshType].SetColor(Globals.RGBA(Grass[(int)x, (int)y, i].ColorR, Grass[(int)x, (int)y, i].ColorG, Grass[(int)x, (int)y, i].ColorB, Transparency));<br />
						GrassMeshes[Grass[(int)x, (int)y, i].MeshType].Render();<br />
					}<br />
				}<br />
				else<br />
				{<br />
					GrassMeshes[Grass[(int)x, (int)y, i].MeshType].SetColor(Globals.RGBA(Grass[(int)x, (int)y, i].ColorR, Grass[(int)x, (int)y, i].ColorG, Grass[(int)x, (int)y, i].ColorB, 1));<br />
					GrassMeshes[Grass[(int)x, (int)y, i].MeshType].Render();<br />
				}<br />
					<br />
			}<br />
		}<br />
	}<br />
}<br />

And this is the GrassType class:

<br />
using System;<br />
using MTV3D65;<br />
<br />
namespace Template<br />
{<br />
	/// <summary><br />
	/// Summary description for GrassType.<br />
	/// </summary><br />
	public class GrassType<br />
	{<br />
<br />
		public int MeshType;<br />
		public MTV3D65.TV_3DVECTOR Position;<br />
		public MTV3D65.TV_3DVECTOR Size;   //maybe you don't need this<br />
		public float ColorR;<br />
		public float ColorG;<br />
		public float ColorB;<br />
<br />
		public GrassType()<br />
		{<br />
			MeshType = 0;<br />
			Position = new TV_3DVECTOR();<br />
			Size = new TV_3DVECTOR();<br />
			ColorR = 0;<br />
			ColorG = 0;<br />
			ColorR = 0;<br />
		}<br />
	}<br />
}<br />

I get my Error when i fist try to acces the array:
Grass[x, y, i].Position.x = PosX;

I really dont know why, because i init my array correcly (atleast i think).

Do u guys know what im doing wrong here?

Re: 'System.NullReferenceException' inside an Array

S. Senthil Kumar9-May-05 23:28

S. Senthil Kumar

9-May-05 23:28

Vinnepin wrote:
GrassType[,,] Grass = new GrassType[(int)NumberOfTiles, (int)NumberOfTiles, (int)GrassNumber];

You've only allocated memory for the array. For each index in that array, you need to call new GrassType() to allocate memory for each object, before attempting to use it.

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

Re: 'System.NullReferenceException' inside an Array

mav.northwind9-May-05 23:40

mav.northwind

9-May-05 23:40

You've allocated the array for your GrassType objects, but didn't instantiate the array elements.
Add
Grass[x,y,i] = new Grass();
after
MeshRandom = (float)random.NextDouble();
and you should be fine.

mav

How to unzip file whith C#???

Anonymous9-May-05 22:50

Anonymous

9-May-05 22:50

Fi all.
I need to write application that can over view ziped files
and for each one of them, show what's in it.
can someone give me some leads???

10x
Assaf

Re: How to unzip file whith C#???

Dan_P9-May-05 23:06

Dan_P

9-May-05 23:06

Have a look at this lib:

http://www.icsharpcode.net/OpenSource/SharpZipLib/Default.aspx[^]

help.about use xsl in C#

dagco9-May-05 22:02

dagco

9-May-05 22:02

Hi,everyone.
Recently,I transform a XML document using a xsl document in a project.I use
"document('')" to replace self.when I program by c#,I find it couldn't work .The XPATH word about "document('')" isn't explain,the c# word is
xslt.Transform(nav, null, s, null);
This is my xml
<?xml version="1.0" encoding="utf-8" ?>
<?xml-stylesheet type="text/xsl" href="viewer.xsl" ?>
<resultset>
<result>
<custname>Tom</custname>
<sex>2</sex>
<addr2>dfd</addr2>
<addr1>dff</addr1>
<customerid>145f3444-302f-407b-b6d5-c8aeaee9b253</customerid>
</result>
<result>
<custname>John</custname>
<sex>2</sex>
<addr2>ddd</addr2>
<addr1>sss</addr1>
<customerid>9099cc4d-ef82-47e6-ab3b-7b2c7d091a55</customerid>
</result>
</resultset>

This is my xsl ,it is in Cache
<?xml version="1.0" encoding="utf-8" ?>
<xsl:transform version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:map="maps.uri">
<xsl:template match="/resultset"><resultset><xsl:apply-templates />
</resultset>
</xsl:template><xsl:template match="result"><result><xsl:for-each select="*">
<xsl:variable name='atrname' select='name()'/><xsl:variable name='atrvalue' select='text()'/>
<
<xsl:value-of select='$atrname'/>
<xsl:if test="document('')/xsl:transform/map:stringmap[AttributeName=$atrname and AttributeValue=$atrvalue]/value!=''">
name="<xsl:value-of select="document('')/xsl:transform/map:stringmap[AttributeName=$atrname and AttributeValue=$atrvalue]/value" />"
</xsl:if>
>
<xsl:value-of select='$atrvalue'/>
</
<xsl:value-of select='$atrname'/>
>
</xsl:for-each>
</result>
</xsl:template>
<map:stringmap>
<AttributeName>sex</AttributeName>
<AttributeValue>1</AttributeValue>
<value>M</value>
</map:stringmap>
<map:stringmap>
<AttributeName>sex</AttributeName>
<AttributeValue>2</AttributeValue>
<value>F</value>
</map:stringmap>
</xsl:transform>

I want get the 'value''s value from the xsl if it can meet my need;It word well in IE.

What can I do ?

How to get table names and relations in oracle database?

oohungoo9-May-05 22:01

oohungoo

9-May-05 22:01

can any body help me?

Open a Word/Excel document without saving!

fatihsen9-May-05 22:01

fatihsen

9-May-05 22:01

Hello, I am trying to open a word or excel document in browser. However, each time it asks open,save,cancel with a dialog box. I want to only open the file. Is there any way to do this operation? I tried the code indicated below,but it opens always a dialog box with open,save,cancel buttons. I would be glad if someone help me.

Thanks.

Response.ClearContent();
Response.ClearHeaders();
Response.Clear();
Response.ContentType = "application/x-msexcel";
Response.Charset = "";
Response.AddHeader("Content-Disposition", "inline; filename=" + dokname); Response.AddHeader("Content-Length",fileLength);

Response.WriteFile(fileUrl);
Response.Flush();
Response.Close();

Fatih Sen

a problem with DataGrid

inew9-May-05 20:58

inew

9-May-05 20:58

Dear All,
In .Net, DataGrid allow mutiselect items is default.
I want a single select DataGrid. Can you help me?
Thanks!

quangthien

Re: a problem with DataGrid

esjq9-May-05 23:47

esjq

9-May-05 23:47

Hi!

Set the property RowHeaderVisible of the datagrid to false.

HTH Smile | :)

Passing a listbox to a method.

Anonymous9-May-05 19:58

Anonymous

9-May-05 19:58

Beginners question.
How do I pass listbox control to a class method and obtain access to the .items collection?

Can you point me to some sample code?

Thanks.

Re: Passing a listbox to a method.

Heath Stewart9-May-05 21:21

Heath Stewart

9-May-05 21:21

You would pass a reference to the control the same way you'd pass any variable to a method as a parameter:

void ClearList(ListBox listBox)
{
  listBox.Items.Clear();
}
 
void Example()
{
  ListBox listBox = new ListBox();
  ClearList(listBox);
}

This posting is provided "AS IS" with no warranties, and confers no rights.

Software Design Engineer
Developer Division Customer Product-lifecycle Experience
Microsoft

[My Articles] [My Blog]

PowerStatus()

victor_ba859-May-05 18:04

victor_ba85

9-May-05 18:04

Hi, i was trying to retrieve information about the status of the battery, and to access the properties i tried to create an instance like the following:

PowerStatus bat = new PowerStatus();

But the error that i receive is that the class PowerStatus doesn't have a constructor defined and when i checked the class it doesn't have the constructor like other classes, you know the one called "PowerStatus()",so i´m wondering: am i doing something wrong?? or is a problem of the .NET Framework 1.1 ??cause i tried different ways to declare the same thing

I appreciate your help

Re: PowerStatus()

Christian Graus9-May-05 18:18

Christian Graus

9-May-05 18:18

A class that doesn't have a public constructor typically has only static methods, or is created via a factory class ( Bitmap for example is a class that works both ways, it has a constructor, and is it's own factor, with a number of static FromXXX methods ).

Here's the MSDN page that has a code sample to do what you want:

http://winfx.msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/winfx/ref/ns/system.windows.forms/c/powerstatus/powerstatus.asp[^]

Christian Graus - Microsoft MVP - C++

Re: PowerStatus()

Heath Stewart9-May-05 21:29

Heath Stewart

9-May-05 21:29

As Christian said, if it doesn't declare a public default constructor you can't instantiate it using the void parameter list. The PowerStatus class in .NET 2.0 does declare any public constructor, actually, meaning that you can't instantiate it.

According to the documentation, you can obtain a reference to it using the static SystemInformation.PowerStatus property:

PowerStatus status = SystemInformation.PowerStatus;
Console.WriteLine("Battery life remaining: {0}",
  status.BatteryLifePercent == 255f ? "Unknown" : status.BatteryLifePercent);

This posting is provided "AS IS" with no warranties, and confers no rights.

Software Design Engineer
Developer Division Customer Product-lifecycle Experience
Microsoft

[My Articles] [My Blog]

"Setup-Wizard-like" layout manager in C# ?

erajsri9-May-05 18:02

erajsri

9-May-05 18:02

Hi,
I'm building an app in C#. It's a Windows App and it needs this common functionality ( we probably get to see in many windows apps ) where the user can keep on pressing the "Next" button when he finished entering a certain amount of data to go to the next level / display different controls.
The situation Im trying to explain is similar to a Setup program that executes an installation, while you keep on pressing the "Next" button.

So how can i achieve this in C# ? I know that in Java there are several Layout Managers like Card Layout to handle this type of situations. The only way possible I think is to add all the controls to be displayed in each step to a collection of Panels and then toggle their visibilty as needed.

But isnt there any easier way like in Java to get the job done ?

Thanx in advance ! Smile | :)

Re: "Setup-Wizard-like" layout manager in C# ?

Christian Graus9-May-05 18:15

Christian Graus

9-May-05 18:15

If you want to show a whole lot of different screens, then I don't see a simpler way of doing it than creating panels as seperate user controls, then adding them all to your form. I'd put the page names into an array, the pages into a hash table by name, and add methods for go forward and backwards that look up the right panel to make visible, if you call an internal method that's a lot easier than trying to hide all panels but one in a lot of different places.

Christian Graus - Microsoft MVP - C++

Re: "Setup-Wizard-like" layout manager in C# ?

ChesterPoindexter10-May-05 2:53

ChesterPoindexter

10-May-05 2:53

www.codeproject.com/cs/miscctrl/magicwizard.asp

The Magic tool kit has a fairly easy to use wizard you might want to look at....

Re: "Setup-Wizard-like" layout manager in C# ?

Christian Graus10-May-05 12:53

Christian Graus

10-May-05 12:53

You should post this as a response to the original poster, so he gets an email notification of it.

Christian Graus - Microsoft MVP - C++

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.