ASP .Net Gridview bind to data only when clicking update - asp.net

Question

Here's how I want the control to work. Click edit on a row in gridview. There's a textbox in one of the columns, I would like it to be blank even though there's data in the database for that column, but when I click update I would like whatever new text the user entered to update the database for that column. It would be one-way databinding, but the other way?

Answer 1

Here's how I did it using an sql datasource with the select,update and delete methods generated.
First, you'll need to make any column that you want to edit like this a template field with an item template and and edit item template:
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
DataKeyNames="ID" DataSourceID="SqlDataSource1"
onrowupdating="GridView1_RowUpdating">
<Columns>
<asp:TemplateField HeaderText="City" SortExpression="City">
<ItemTemplate>
<asp:Label runat="server" Text='<%# Eval("City") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox runat="server" ID="txtCityEdit" Text=""></asp:TextBox>
</EditItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
Next handle the gridview's on update event:
protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
//find the value control who's value you want
TextBox tb = (TextBox)GridView1.Rows[e.RowIndex].FindControl("txtCityEdit");
//since we are not using a bound column for city we need to explicitly insert the value
//into the update parameter.
SqlDataSource1.UpdateParameters["City"].DefaultValue = tb.Text;
}
Even if you are using something other than an SQL Datasource this should be the basic solution.

Answer 2

// Find notes textbox
TextBox tb = (TextBox)MyActiveReferrals.Rows[e.RowIndex].FindControl("NotesTextBox");
e.NewValues.Add("Notes", tb.Text);
I used a linq data source.