how can I catch this error?
DropdownList1.SelectedValue = strText;
This is the error:
Selected Value of DropdownList1 is invalid because it does not appear in the list of items.
Can I catch it with something like strText exist in dropdownlist1?
You can use DropDownList.Items.FindByValue
if( ItemCollection.FindByValue(strText) != null)
{
DropdownList1.SelectedValue = strText;
}