c# - 使用 C# 时阻止用户在文本框中输入数值

Question

当下拉列表值为 MBID 时，我试图阻止用户在搜索条件文本框中输入数值代码有效我只需要有关如何解决验证问题的帮助

C#代码

protected bool searchData()
{
      string val = DropDownList1.SelectedItem.Value;
 switch (val)
  {
      case "MBID":

       using (SqlConnection con = new SqlConnection(WebConfigurationManager.ConnectionStrings["Molecular"].ConnectionString))
         {
             con.Open();
               using (SqlCommand cmd = new SqlCommand(@"SELECT  count(*)

                        from Patient  where MBID = @SearchCriteria ", con))
                {

                        DataTable dt = new DataTable();
                        SqlDataAdapter da = new SqlDataAdapter(cmd);
                        int userCount = (Int32)cmd.ExecuteScalar();
                        da.Fill(dt);
           }
       }

    }

  }

搜索按钮调用下面的代码

protected void btnSearch_Click(object sender, EventArgs e)
    {
        if (FormValidation()) if (searchData())
         {

            BindGrid();
            inputUpdateFornData();

        }

    }

HTML代码

<asp:DropDownList ID="DropDownList1" runat="server"  OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
      <asp:ListItem Value="MBID">MBID</asp:ListItem>
      <asp:ListItem Value="HPNumber">HP Number</asp:ListItem>
      <asp:ListItem Value="NHSNumber">NHS Number</asp:ListItem>

我不能使用下面的代码，因为可以为下拉列表的其他选项输入数值

<asp:TextBox ID="txtSearchCriteria" runat="server />
<asp:CompareValidator ID="cv" runat="server"     ControlToValidate="txtSearchCriteria" Type="Integer"
  Operator="DataTypeCheck" ErrorMessage="Value must be an integer!" />

Answer 1

这是怎么做的:

        try
        {
            int d = int.Parse(txtSearchCriteria.Text);
            //if works str is a number
        }
        catch (Exception e)
        {
            Console.WriteLine("It isn't a number!");
        }