Mega Code Archive
Adding an asynchronous callback to validate data (C#)
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using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Text;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebControlLibrary1
{
[DefaultProperty("Text")]
[ToolboxData("<{0}:WebCustomControl1 runat=server></{0}:WebCustomControl1>")]
public class WebCustomControl1 : WebControl, ICallbackEventHandler
{
private string text;
[Bindable(true)]
[Category("Appearance")]
[DefaultValue("")]
[Themeable(false)]
public string Text
{
get
{
return text;
}
set
{
text = value;
}
}
protected override void Render(HtmlTextWriter output)
{
output.RenderBeginTag(HtmlTextWriterTag.Div);
output.AddAttribute(HtmlTextWriterAttribute.Type, "text");
output.AddAttribute(HtmlTextWriterAttribute.Id, this.ClientID);
output.AddAttribute(HtmlTextWriterAttribute.Name, this.ClientID);
output.AddAttribute(HtmlTextWriterAttribute.Value, this.Text);
output.AddAttribute("OnBlur", "ClientCallback();");
this.AddAttributesToRender(output);
output.RenderBeginTag(HtmlTextWriterTag.Input);
output.RenderEndTag();
output.RenderEndTag();
}
protected override void OnPreRender(EventArgs e)
{
Page.ClientScript.RegisterStartupScript(
typeof(Page),
"ControlFocus", "document.getElementById('" + this.ClientID + "').focus();",
true);
Page.ClientScript.RegisterStartupScript(
typeof(Page), "ClientCallback",
"function ClientCallback() {" +
"args=document.getElementById('" + this.ClientID + "').value;" +
Page.ClientScript.GetCallbackEventReference(this, "args",
"CallbackHandler", null, "ErrorHandler", true) + "}",
true);
}
#region ICallbackEventHandler Members
public void RaiseCallbackEvent(string eventArgument)
{
int result;
if (!Int32.TryParse(eventArgument, out result))
throw new Exception("The method or operation is not implemented.");
}
public string GetCallbackResult()
{
return "Valid Data";
}
#endregion
}
}
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