How Can I make the event of Activate Windows to run only one time?
In order to make the event of Activate Windows to run only one time, I write the code below
this.Activated-=new System.EventHandler(this.Form1_Activated);
Is it correct? but It certain can work well. but it seems it is not a good code.
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using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data; namespace WindowsApplication1
{ publicclass Form1 : System.Windows.Forms.Form
{ private System.ComponentModel.Container components =null; public Form1()
{ InitializeComponent(); } protectedoverridevoid Dispose(bool disposing )
{
if( disposing )
{
if (components !=null)
{
components.Dispose();
}
}
base.Dispose( disposing );
} #region Windows privatevoid InitializeComponent()
{ this.AutoScaleBaseSize =new System.Drawing.Size(6, 14);
this.ClientSize =new System.Drawing.Size(292, 266);
this.Name = "Form1";
this.Text = "Form1";
this.Activated +=new System.EventHandler(this.Form1_Activated); }
#endregion
[STAThread]
staticvoid Main()
{
Application.Run(new Form1());
}
privatevoid Form1_Activated(object sender, System.EventArgs e)
{
this.Activated-=new System.EventHandler(this.Form1_Activated);
}
}
}
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[2846 byte] By [
CUIWEI] at [2007-12-16]
The code is certainly correct.
I find it better to override the method that actually raises the event, instead of attaching to it. However this is typically a personal preference.
For example:
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public class Form1 : Form
{
...
private bool _FirstActivate = true; protected override OnActivated(EventArgs e)
{
if (_FirstActivate)
{
_FirstActivate = false;
...
} base.OnActivated(e);
}
}
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Have you tested it? My initial reaction was that this can't work.
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this.Activated-=new System.EventHandler(this.Form1_Activated);
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here you are removing a NEW event handler for the method, not the one allready added.
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private void Form1_Activated(object sender, EventArgs e) { this.Activated -= activEventHandler; } //these two items is to be put in the designer in whidbey
private System.EventHandler activEventHandler; this .Activated += (activEventHandler = new System.EventHandler(this.Form1_Activated));
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