在gridview中的特定控件上添加事件

Question

I have a scenario, where i need to attach an event (textchanged) to a textbox. It should only trigger, if the code is "code2". Please check the below code ; The value_TextChanged doesn't get triggered:

<asp:GridView runat="server" ID="gv1"  AutoGenerateColumns="false" 
            onrowcreated="gv1_RowCreated1" >
    <Columns>
    <asp:TemplateField>
    <ItemTemplate>
    <asp:Label runat="server" ID="code" Text='<%# Bind("[code]") %>'></asp:Label>
    </ItemTemplate>
    </asp:TemplateField>
    <asp:TemplateField>
    <ItemTemplate>
    <asp:TextBox runat="server" ID="val" Text='<%# Bind("[value]") %>'></asp:TextBox>
    </ItemTemplate>
    </asp:TemplateField>
    </Columns>
    </asp:GridView>

protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                DataBind();
            }
        }

        void DataBind()
        {
            DataTable dt = new DataTable();
            dt.TableName = "tb1";
            dt.Columns.Add("code");
            dt.Columns.Add("value");
            dt.Rows.Add("code1", "Red");
            dt.Rows.Add("code2", "Green");
            dt.Rows.Add("code3", "Blue");
            gv1.DataSource = dt;
            gv1.DataBind();
        }

        protected void gv1_RowCreated1(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                string code = (String)DataBinder.Eval(e.Row.DataItem, "code");
                TextBox value = (TextBox)e.Row.FindControl("val");
                if (code == "code2")
                {
                    value.AutoPostBack = true;
                    value.TextChanged += new EventHandler(value_TextChanged);
                }
            }
        }

        void value_TextChanged(object sender, EventArgs e)
        {
            throw new NotImplementedException();
        }

Answer 1

To trigger TextChange you need to add AutoPostBack="true" in your Markup; For attaching an event with TextChange you need not to depend gv1_RowCreated that also you can specify in the markup.

<asp:TextBox AutoPostBack="true" OnTextChanged="value_TextChanged" 
runat="server" ID="val" Text="" ></asp:TextBox>

Please note one more thing, the event will trigger when the textBox loss its focus