Question

I have datagrid which shows activity name and a checkbox column. User checks the checkbox if he/she wants to select that activity and presses submit button to successfully add it.

If user wants to un-check the checked checkboxes i have to make certain validation to check whether that activity is currently associated with any other thing or not.

How can i do that?

Answer 1

If the validation can be done on client side, add a template field to the GridView, add a CheckBox in the template field and attach a JavaScript event to it

<asp:TemplateField HeaderText="IsActive">
    <ItemTemplate>
        <asp:CheckBox ID="chkActive" Checked='<%# Bind("IsActive") %>' runat="server" onClick="checkboxClicked(this)" />
    </ItemTemplate>
</asp:TemplateField>

Handle the JavaScript event and perform the validation. If the user unchecked the checkbox and validation fails, you may prompt the user and check the checkbox in JavaScript as shown:

function checkboxClicked(src) {
    if (!src.checked) {
        var valid;
        //Perform validation and set a boolean value to the variable valid
        if(!valid)
            src.checked = true;
     }
}

This might help you in achieving what you are looking for. If you need any other help, you may put a comment.