AutoPostBack
true に設定して、そのTextChanged
イベントを処理できます。
<asp:GridView ID="GridView1" runat="server" EmptyDataText="It's Empty.">
<Columns>
<asp:TemplateField HeaderText="Name">
<ItemTemplate>
<asp:TextBox ID="txtName"
runat="server"
Text='<%#Eval("Name") %>'
AutoPostBack="true"
OnTextChanged="NameChanged" >
</asp:TextBox>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</GridView>
コードビハインドで:
protected void NameChanged(Object sender, EventArgs e)
{
var txtName = (TextBox) sender;
var row = (GridViewRow) txtName.NamingContainer;
// you could find other controls in this GridViewRow via
// row.FindControl("ControlID") in case of a TemplateField or
// row.Cells[0].Text (0 = index of column) in case of a BoundField
}