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-   -   System.NullReferenceException (http://www.go4expert.com/forums/systemnullreferenceexception-t6010/)

tanvirtonu 24Aug2007 11:38

System.NullReferenceException
 
f I just add a simple textbox/richtext box in C# design window and run it, An exception occures- " System.NullReferenceException"

My code frm the code window is as follows-
Code:

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace TestDemo2
{
        /// <summary>
        /// Summary description for Form1.
        /// </summary>
        public class Form1 : System.Windows.Forms.Form
        {
                private System.Windows.Forms.RichTextBox richTextBox1;
                /// <summary>
                /// Required designer variable.
                /// </summary>
                private System.ComponentModel.Container components = null;

                public Form1()
                {
                        //
                        // Required for Windows Form Designer support
                        //
                        InitializeComponent();

                        //
                        // TODO: Add any constructor code after InitializeComponent call
                        //
                }

                /// <summary>
                /// Clean up any resources being used.
                /// </summary>
                protected override void Dispose( bool disposing )
                {
                        if( disposing )
                        {
                                if (components != null)
                                {
                                        components.Dispose();
                                }
                        }
                        base.Dispose( disposing );
                }

                #region Windows Form Designer generated code
                /// <summary>
                /// Required method for Designer support - do not modify
                /// the contents of this method with the code editor.
                /// </summary>
                private void InitializeComponent()
                {
                        //Exception shows here- Highlighted after compile
                        this.richTextBox1 = new System.Windows.Forms.RichTextBox();

                        this.SuspendLayout();
                        //
                        // richTextBox1
                        //
                        this.richTextBox1.Location = new System.Drawing.Point(128, 40);
                        this.richTextBox1.Name = "richTextBox1";
                        this.richTextBox1.TabIndex = 0;
                        this.richTextBox1.Text = "richTextBox1";
                        //
                        // Form1
                        //
                        this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
                        this.ClientSize = new System.Drawing.Size(456, 286);
                        this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                this.richTextBox1});
                                this.Name = "Form1";
                                this.Text = "Form1";
                                this.Load += new System.EventHandler(this.Form1_Load);
                                this.ResumeLayout(false);

                }
                #endregion

                /// <summary>
                /// The main entry point for the application.
                /// </summary>
                [STAThread]
                static void Main()
                {
                        Application.Run(new Form1());
                }

                private void Form1_Load(object sender, System.EventArgs e)
                {

                }
        }
}

After I run the same code the following message is shown-

"An unhandled exception of type 'System.NullReferenceException' occurred in system.windows.forms.dll

Additional information: Object reference not set to an instance of an object. "

It highlights the following line of the code-

"this.richTextBox1 = new System.Windows.Forms.RichTextBox();"


IT IS really getting on my nerves.What the hell is this exception about. I didnt write a single code in it. I did it frm design window. THen why do they show such an exception. What else to do to get it right. PLs help me.

shabbir 24Aug2007 17:32

Re: System.NullReferenceException
 
I am not sure why there is an error but it looks like you have just used the Generated code and nothing of your own.

tanvirtonu 26Aug2007 03:58

Re: System.NullReferenceException
 
Brother where the .Net software cant make it out with its own generated code,You r telling me to add my code. :eek: If it cant run a simple program made/coded all by itself, there is no use writing my code.

tanvirtonu 26Aug2007 04:07

Re: System.NullReferenceException
 
One thing is dat I hav two operating systems.One in drive c and another one(XP)is in drive D and I have installed .Net in XP, I mean drive D. But in Xp I installed MS.Net in drive E bcos there was little space in the system drive-D. Is it making anu problem. I even reinstalled .Net and tried again just after adding a richtextbox.It says the same thing-

"An unhandled exception of type 'System.NullReferenceException' occurred in system.windows.forms.dll

Additional information: Object reference not set to an instance of an object. "

See the problem is in the system.windows.forms.dll.
I dont know what it means. Whatever I add makes no problem except for RichTextBox-this is the main problem of every RICH!! object of the world

shabbir 26Aug2007 08:13

Re: System.NullReferenceException
 
Quote:

Originally Posted by tanvirtonu
Brother where the .Net software cant make it out with its own generated code,You r telling me to add my code. :eek: If it cant run a simple program made/coded all by itself, there is no use writing my code.

Try to read the replies. If you are not a good reader you should be trying it out of your own. I have told just the opposite.


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