Validation for a datagrid column

[steve.edison]

I have been trying to validate a textbox value, but unfortunately, the
test for its validity is a function that must look up a value in a SQL
database. The function returns true or false and that will determine
the validity of the entry which is itself in a datagrid. Can anyone
provide a sample of how this code would look? Sadly, I am terribly new
to ASP.NET, so if you could also elaborate on whether any specific code
must be in the ASP or the code-behind, I would appreciate it.

 

[Guest]

I would suggest having a CustomValidator to do this. Add the custom validator
control to the .aspx page and in the .aspx.cs or .vb file, capture the
ServerValdiateEvent . In this event, write the code to connect to the
database and verify the value entered.
//Untested Pseudocode
public void ServerValidation(object sender, ServerValidateeventArgs args)
{
if(ValidateAgainstDB(txtVal.Text))
{
args.IsValid=false;
}

}
Here ValidateAgainstDB should verify the value against the database and
should return a true if the value is valid and false for Invalid