c# - Simple Int.Parse addition

Question

I'm giving int input in Textbox1 and Textbox2, then the sum of both will be display on Label1. Can anyone show me how it work??? My int.parse not working.

.asxp

 <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>
         <asp:Button ID="Button1" runat="server" Text="Display" />

     </div>

.aspx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace MQM_System
{   
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }
        protected void Button1_Click(object sender, System.EventArgs e)
        {
            int sum = 0;

            sum = int.Parse(TextBox1.Text) + int.Parse(TextBox2.Text);
            Label1.Text = sum.ToString();
        }
    }
}

Answer 1

您必须将 Button1_Click事件处理程序分配给Buttonevent OnClick。

<asp:Button ID="Button1" runat="server" Text="Display" OnClick="Button1_Click" />

此外，您应该使用TryParse方法 ( msdn ) 而不是事件处理程序中的Parse方法。Button1_Click

Answer 2

Int.Parse 的问题在于它需要一个有效数字，否则会引发异常。
您可以使用 TryParse 来实现更好的控制

  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();