QUICK HELP: C#.Net Syntax Error

[Bluebarry]

Hey, I need some help on this piece of code.

Overview:
I created a wizard program, the wizard pages are included in a sperate DLL file which my project has references too, all controls on the wizard pages have their modifiers set to public. I have no problem communicating with the wizard pages from my application, however I'm getting an error in this section when trying to read all the controls at once.

foreach (TextBox tbValidate in DbWizPage1.Controls)
{
if (tbValidate.Tag == "Required")
{
if (tbValidate.Text == string.Empty)
{
DbWizPage1.errorProvider1.SetError(tbValidate,"Required Field");
}
else
{
DbWizPage1.errorProvider1.SetError(tbValidate, "");
}
}
}

I'm trying to check all the text box controls on the page. Locate the controls that are required and check to insure data has been inserted in them. I'm not to the point of validating the data, just want to insure it's there. This should check every text box on page1, find out if it's required, if so, then check to insure data is available, if not tell the error provider to mark that control as invalid.

I keep getting an invalid cast error on the first line. If there is another solution I would be open to it. There are about 30 controls on page one, and many more on additional pages. I don't want to have to include code to check every single field, that would just be insane. I had a lovely idea of taging the controls as required, checking the entire collection and disreguarding the contorls not required, but it dosen't like my method I guess.

Site point once again dose not allow formatting of code samples since it completely destroyed it again... wish they'd fix that bug.

Thanks, Everyone