c# - 使用文本框上的 OnChange 事件进行简单显示

Question

如何使用OnChange事件在Textbox1和Textbox2中输入值后立即将结果显示在Label1上？

    <div>
             <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
             <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
             <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>

         </div>
---------------------------------------------------------------------------------------
//Code behind

     int num1;
      if(!Int32.TryParse(TextBox1.Text, out num1))
      {
          Label1.Text = "Not a valid number";
          return;
      }
      int num2;

      if(!Int32.TryParse(TextBox2.Text, out num2))
      {
          Label1.Text = "Not a valid number";
          return;
      }
      sum = num1 + num2;
      Label1.Text = sum.ToString();

Answer 1

要使用 TextChangedEvent，您需要在代码中添加 TextChangedEvent 事件处理程序，并在标记中设置 AutoPostBack=true

<asp:TextBox ID="TextBox2" runat="server" OnTextChanged="TextBox2_TextChanged" AutoPostBack="true"></asp:TextBox>

隐藏代码

    protected void TextBox2_TextChanged(object sender,EventArgs e)
    {
       int num1;
       if(!Int32.TryParse(TextBox1.Text, out num1))
       {
          Label1.Text = "Not a valid number";
          return;
       }
       int num2;

      if(!Int32.TryParse(TextBox2.Text, out num2))
      {
         Label1.Text = "Not a valid number";
         return;
      }
      sum = num1 + num2;
      Label1.Text = sum.ToString();
    }