A problem in Error providers

You did not clear the error when the data is valid. You also call SetError with non-empty error message unconditionally. What's the criteria for validity? Non-empty value? Than call SetError depending on it:

private void tbxWidthBackIamge_Validated(object sender, EventArgs e) {
    if (tbxBackImage.Text.Trim() == string.Empty)
       this.errBackWidth.SetError(tbxWidthBackIamge, "Enter the Width");
    else
       this.errBackWidth.SetError(tbxWidthBackIamge, string.Empty);
}

Pay attention, I use string.Empty instead of "" (never do it). I also suggest to add Trim assuming that a string containing only blank space characters is also invalid. If my assumption is wrong, simply remove Trim.

Better yet, use anonymous delegate:

myControl.Validated += delegate(object sender, System.EventArgs eventArgs) {
    if (tbxBackImage.Text.Trim() == string.Empty)
       this.errBackWidth.SetError(tbxWidthBackIamge, "Enter the Width");
    else
       this.errBackWidth.SetError(tbxWidthBackIamge, string.Empty);
}

With C# v.3 or v.4 you could use the even better syntax with lambda form of the delegate:

myControl.Validated += (sender, eventArgs) => {
    if (tbxBackImage.Text.Trim() == string.Empty)
       this.errBackWidth.SetError(tbxWidthBackIamge, "Enter the Width");
    else
       this.errBackWidth.SetError(tbxWidthBackIamge, string.Empty);
}

See the code sample on this MSDN help page: http://msdn.microsoft.com/en-us/library/system.windows.forms.errorprovider.aspx[^].

Does your code even compile? I mean, what is errBackHeight which you dispose. Does it implement IDisposable? Why disposing anything on error? Just checking.

—SA