Prevent Page PostBack on TextBox TextChanged event using Update Panel in ASP.Net

I have textbox.if i am enter anything in textbox its postback then binding gridview.i dont want to postback method in this event.

Even i used update pannel to prevent postback.

Aspx

<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
	<Triggers>
		<asp:AsyncPostBackTrigger ControlID="Button1" EventName="Click" />
	</Triggers>
<ContentTemplate>
	<tr>
		<td>
			<asp:TextBox ID="txtProdCode" runat="server" CssClass="form-control" Font-Bold="True"
			Width="150px" Height="30px" AutoPostBack="true" OnTextChanged="txtProdCode_TextChanged"></asp:TextBox>
		</td>
		<td>
			<asp:CheckBox ID="chkComp" runat="server" Text="Complimentary" Width="136px" />
		</td>
	</tr>
</ContentTemplate>
</asp:UpdatePanel>

Aspx.cs

protected void txtProdCode_TextChanged(object sender, EventArgs e)
{
	DataTable dt = new DataTable();
	string bid = txtBranchId.Text;
	GetValues1();
	dt = BL.Fill_Grid("SELECT distinct aibProdTypeMast.ProdTypeName, aibProdMast.ProdName, aibOrderDetails.Discription, aibOrderDetails.Qty, aibOrderDetails.Amount, aibOrderDetails.MRP, aibOrderDetails.PerDiscount, aibOrderDetails.Tax, aibProdRegistryBO.ProdCode FROM aibProdMast INNER JOIN aibProdTypeMast ON aibProdMast.ProdTypeID = aibProdTypeMast.ProdTypeID INNER JOIN aibOrderDetails ON aibProdMast.ProdID = aibOrderDetails.ProdID INNER JOIN aibProdRegistryBO ON aibProdMast.ProdID = aibProdRegistryBO.ProdID WHERE (aibProdRegistryBO.ProdCode='" + GC.ProdCode + "') AND (aibOrderDetails.BranchID = '" + bid + "')");
	gvwOrderDetails.DataSource = dt;
	gvwOrderDetails.DataBind();
}