Question

Suppose I don’t want to use

if (string.IsNullOrEmpty(textbox1.Text))
{
     textbox1.Text = null;
}

for every textbox controls in form, is there a easier way to do it ?

Answer 1

You can iterate through the ControlCollection of the given form, e.g. frmMain.Controls
Now this will be the basic Control object, so you would need a test to see if it is of type TextBox.

.NET 2.0 – you’ll have to check this manually
.NET 3.0+ – use the .OfType<TextBox> extension method to give you only a list of IEnumerable<TextBox>

Note that iterating through this from the form will only give you text boxes on that form. If you bind text boxes to a container it won’t show up there.

Safest bet would be to write a recursive function that walks through all the control collections and passes the reference to your test function to perform your test and update.