how to perform validation on textbox in templatecolumn of datagrid?

[asp.net_vb.net]

In my DataGrid i've created a textbox in one of the template column which means all rows of that template column will have the same ID for the textbox.

How do I perform validation on each textbox only when that row is selected using the Select event only

Thx!

[mendhak]

Place a validator in the templatecolumn too.

In the ItemDataBound event, do a FindControl() for the textbox and the validator, and set the validator's ControlToValidate property to the textbox... assign the textbox's ClientId property to the ControlToValidate property.

[asp.net_vb.net]

Place a validator in the templatecolumn too.

In the ItemDataBound event, do a FindControl() for the textbox and the validator, and set the validator's ControlToValidate property to the textbox... assign the textbox's ClientId property to the ControlToValidate property.

Dim validator As System.Web.UI.WebControls.RegularExpressionValidator
        validator = CType(e.Item.FindControl("Regularexpressionvalidator123"), System.Web.UI.WebControls.RegularExpressionValidator)
 
        Dim txtbox As System.Web.UI.WebControls.TextBox
        txtbox = CType(e.Item.FindControl("textbox"), System.Web.UI.WebControls.TextBox)
       
        validator.ControlToValidate = txtbox.ClientID

this is what I typed in the itemdatabound event but there is an error saying

Line 612:        txtbox = CType(e.Item.FindControl("textbox"), System.Web.UI.WebControls.TextBox)
Line 613:       
Line 614:        validator.ControlToValidate = txtbox.ClientID

[asp.net_vb.net]

Place a validator in the templatecolumn too.

In the ItemDataBound event, do a FindControl() for the textbox and the validator, and set the validator's ControlToValidate property to the textbox... assign the textbox's ClientId property to the ControlToValidate property.

the purpose is to validate the textbox for that row only when a select button is clicked but not other textboxes located in the same column. But the problem is that they have the same ID for the txtbox and when the Controltovalidate is set to the textbox ID, it will validate all of the textbox controls which it should not

[mendhak]

OK, a few changes to what I said.

Instead of

validator.ControlToValidate = txtbox.ClientID

put

validator.ControlToValidate = txtbox

That should do it.

Btw, you never said what the error was, but try what I just said right now.

[nemaroller]

That won't work - the ControlToValidate property expects a string, not a control class object.

You never stated what the error was, but you need the UniqueID property.

validator.ControlToValidate = txtbox.UniqueID.

[asp.net_vb.net]

The error is

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error: 


Line 613:        txtbox = CType(e.Item.FindControl("textbox"), System.Web.UI.WebControls.TextBox)
Line 614:       
Line 615:        validator.ControlToValidate = txtbox.UniqueID

[mendhak]

That won't work - the ControlToValidate property expects a string, not a control class object.

You never stated what the error was, but you need the UniqueID property.

validator.ControlToValidate = txtbox.UniqueID.

My bad, but not-so-bad, I had no IDE and Intellisense