The Problem: You are using an asp.net PlaceHolder control and populating it with a collection of custom web controls. You then get “Null Reference Exception” and “Are you missing an assembly?” errors. Your code looks much like this
foreach (string str in strStringList)
{
CustomWebBox cb=new CustomWebBox()[
cb.CustomTitle=str;
myPlaceHolder.Controls.Add(cb);
}
The Cause: The same ID’s are being used over and over agian in the page as the web control repeats.
The Solution: Instead of simply reinitializing the control the “new” keyword, load it manually using Page.LoadControl. That keeps the id tags different and the error is avoided. Your code would look something like this.
foreach (string str in strStringList)
{
CustomWebBox cb=(CustomWebBox)Page.LoadControl("~/CustomWebBox.ascx");
cb.CustomTitle=str;
myPlaceHolder.Controls.Add(cb);
}
That’s it!
This post originally appeared on the Stronico blog – with the absorption of Stronico into Digital Tool Factory this post has been moved to the Digital Tool Factory blog
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Written By Steve French |
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