Dynamically creating CustomValidator in server control

Question

I have a custom server control which wraps a RadEditor (basically a textarea). I am trying to add a CustomValidator to it dynamically, but I keep getting this error on initial pageload

Unable to find control id 'RadEditor1' referenced by the 'ControlToValidate' property of ''.

This is the code I'm using inside my server control to create the CustomValidator:

protected override void OnInit(EventArgs e)
{
    var validator = new CustomValidator();
    validator.CssClass = "validator-error";
    validator.Display = ValidatorDisplay.Dynamic;
    validator.ControlToValidate = this.ID;
    validator.Text = "You've exceeded the maximum allowed length for this field";
    validator.ClientValidationFunction = "checkLength";

    this.Controls.Add(validator);

    base.OnInit(e);
}

Does your server control derive from `RadEditor`? – Michael Liu Apr 06 '12 at 16:27 — Michael Liu, Apr 06 '12 at 16:27
Yes, it does. `public class RichTextEditor : RadEditor {}` – msigman Apr 06 '12 at 16:28 — msigman, Apr 06 '12 at 16:28

score 1 · Accepted Answer · answered Apr 06 '12 at 16:37

1

The problem is that RadEditor implements INamingContainer, so ASP.NET winds up searching among your server control's children for a control named RadEditor1. Of course, it's unsuccessful because RadEditor1 doesn't have a child control named RadEditor1.

The trick I use is to choose a special ID like "." to mean the parent control itself:

protected override Control FindControl(string id, int pathOffset)
{
    return (id == ".") ? this : base.FindControl(id, pathOffset);
}

Then use "." as the ControlToValidate:

validator.ControlToValidate = ".";

answered Apr 06 '12 at 16:37

Michael Liu

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Brilliant. Worked perfectly. – msigman Apr 06 '12 at 17:07
2

Add a ".." for referring to the parent. Might be useful one day. :) – Roman Royter Apr 09 '12 at 01:05

Dynamically creating CustomValidator in server control

1 Answers1