在ASP.NET中计算TextBox的TextChanged（）事件的总数

我有一个小应用程序，如下所示。

在此“物料费率”和“采购订单总计”中为只读字段。我想通过公式（Total = Rate * Qty）计算每个物料数量变化的总数。

我在“物料数量”上进行了编码，TextChanged()并更改AuotoPostBack为True

我尝试的代码如下：

protected void txtMQty_TextChanged(object sender, EventArgs e)
{
 checkTotal();
}

//I am saving Rate in ViewState["Rate"] and retrieving here.
private void checkTotal()
{
 Rate = Convert.ToInt32(ViewState["Rate"]);
 txtMQty.Text = string.Empty;
 if (Rate > 0 && txtMQty.Text == string.Empty)
 {
  txtMRate.Text = Rate.ToString();
  txtTotal.Text = Rate.ToString();
 }
 Regex reg = new Regex("[^0-9]+$");
 var str = txtMQty.Text.ToString();
 str = reg.Replace(str, string.Empty);
 if (str.Length > 0)
 {
 var qty = Convert.ToInt32(txtMQty.Text.ToString());
 int total = (Rate* qty);
 txtTotal.Text = total.ToString();
 }
 }

我还使用UpdatePanel避免往返。我的问题是，当我输入Quantity时txtMQty，TextChaged()事件应该触发但不触发。没有得到什么问题。

我的.aspx页面如下。

<tr>
        <td class="auto-style3">
            Material Quantity</td>
        <td class="auto-style4">
            <asp:TextBox ID="txtMQty" runat="server" Width="87px" AutoPostBack="True" OnTextChanged="txtMQty_TextChanged"></asp:TextBox></td>
        <td>
            <asp:RequiredFieldValidator ID="RFVMQty" runat="server" ForeColor="Red" Display="Dynamic" ControlToValidate="txtMQty" ErrorMessage="Please provide Material Quantity" ValidationGroup="CreateVal"></asp:RequiredFieldValidator>
            <asp:RegularExpressionValidator ID="REVMQty" runat="server" ForeColor="Red" Display="Dynamic" ControlToValidate="txtMQty" ErrorMessage="Please provide proper Quantity in number format" ValidationExpression="^\d+$" ValidationGroup="CreateVal"></asp:RegularExpressionValidator>
        </td>
    </tr>
    <tr>
 <tr>
        <td class="auto-style3">Material Rate</td>
        <td class="auto-style4">
            <asp:UpdatePanel ID="UpdateRate" runat="server">
                <Triggers>
                    <asp:AsyncPostBackTrigger ControlID="txtMQty" EventName="TextChanged" />
                </Triggers>
                <ContentTemplate>
            <asp:TextBox ID="txtMRate" runat="server" Width="87px" ReadOnly="True"></asp:TextBox>
                    </ContentTemplate>
        </asp:UpdatePanel>
                    </td>
        <td></td>
    </tr>
    <tr>
        <td>
            PO Total
        </td>
        <td class="auto-style4">
            <asp:UpdatePanel ID="UpdateTotal" runat="server">
                <Triggers>
                    <asp:AsyncPostBackTrigger ControlID="txtMQty" EventName="TextChanged" />
                </Triggers>
                <ContentTemplate>
            <asp:TextBox ID="txtTotal" runat="server" Width="87px" ReadOnly="True"></asp:TextBox>
                    </ContentTemplate>
        </asp:UpdatePanel>
        </td>
    </tr>
    <tr>