Спасибо за все ваши ответы, но я нашел решение здесь на telerik forum . Я просто вставлю решение здесь на тот случай, если кто-нибудь застрянет на той же проблеме.
ASPX:
<Columns>
<rad:GridTemplateColumn UniqueName="Price" HeaderText="Price">
<EditItemTemplate>
<radI:RadNumericTextBox ID="txtPrice" runat="server">
</radI:RadNumericTextBox>
</EditItemTemplate>
</rad:GridTemplateColumn>
<rad:GridTemplateColumn UniqueName="Quantity" HeaderText=" Number of Items">
<EditItemTemplate>
<radI:RadNumericTextBox ID="txtQuantity" runat="server">
</radI:RadNumericTextBox>
</EditItemTemplate>
</rad:GridTemplateColumn>
<rad:GridTemplateColumn UniqueName="TotalAmount" HeaderText="Total">
<EditItemTemplate>
<radI:RadNumericTextBox ID="txtTotalAmount" runat="server">
</radI:RadNumericTextBox>
</EditItemTemplate>
</rad:GridTemplateColumn>
</Columns>
C #
protected void RadGrid1_ItemDataBound(object sender, GridItemEventArgs e)
{
if (e.Item is GridDataItem && e.Item.IsInEditMode)
{
GridDataItem item = (GridDataItem)e.Item;
RadNumericTextBox txtPrice= item.FindControl("txtPrice") as RadNumericTextBox; // Get the textbox for column Price
RadNumericTextBox txtQuantity= item.FindControl("txtQuantity") as RadNumericTextBox; // Get the textbox for column Quantity
RadNumericTextBox txtTotalAmount= item.FindControl("txtTotalAmount") as RadNumericTextBox; // Get the textbox for column "TotalAmount", if it is template as shown in aspx
txtPrice.Attributes.Add("onFocusout", "return calculate('" + txtPrice.ClientID + "','" + txtQuantity.ClientID + "','" + txtTotalAmount.ClientID + "')");
txtQuantity.Attributes.Add("onFocusout", "return calculate('" + txtPrice.ClientID + "','" + txtQuantity.ClientID + "','" + txtTotalAmount.ClientID + "')");
txtTotalAmount.Attributes.Add("onfocus", "return calculate('" + txtPrice.ClientID + "','" + txtQuantity.ClientID + "','" + txtTotalAmount.ClientID + "')");
}
}
JavaScript:
<script type="text/javascript">
function calculate(price, quantity, totalAmount)
{
var text1 = $find(price); //I used Asp.net Ajax find method
var text2 = $find(quantity);
var text3 = $find(totalAmount);
var total = text1.GetValue() * text2.GetValue();
text3.SetValue(total);
}
</script>