C＃和ASP中的異常處理.Net

我有頁面和SQL數據庫後面的SQL表不允許重複地址名稱。我把它連接到數據庫，並試圖實現嘗試捕捉雄蕊它是工作，但前某些原因不希望顯示錯誤消息C＃和ASP中的異常處理.Net

HTML

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="AdmAddStreet.aspx.cs" Inherits="AdmAddStreet" %> 

<!DOCTYPE html> 

<html xmlns="http://www.w3.org/1999/xhtml"> 
<head runat="server"> 
    <title></title> 
</head> 
<body> 
    <form id="form1" runat="server"> 
    <div> 

     add new address<br /> 
     <asp:TextBox ID="txbAddress" runat="server" Height="22px" Width="348px"></asp:TextBox> 
     <br /> 
     <br /> 
     <asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click1" Width="353px" /> 

     <br /> 
     <br /> 
     <asp:Label ID="DisplayMessage" runat="server" style="color: #FF0000" Visible="false" /> 
     <asp:Label ID="DisplayMessage0" runat="server" style="color: #FF0000" Visible="false" /> 
     <br /> 
     <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:TicketsConnectionString %>" DeleteCommand="DELETE FROM [Streets] WHERE [StrID] = @original_StrID" InsertCommand="INSERT INTO [Streets] ([StrName]) VALUES (@StrName)" OldValuesParameterFormatString="original_{0}" SelectCommand="SELECT * FROM [Streets]" UpdateCommand="UPDATE [Streets] SET [StrName] = @StrName WHERE [StrID] = @original_StrID"> 
      <DeleteParameters> 
       <asp:Parameter Name="original_StrID" Type="Int32" /> 
      </DeleteParameters> 
      <InsertParameters> 
       <asp:Parameter Name="StrName" Type="String" /> 
      </InsertParameters> 
      <UpdateParameters> 
       <asp:Parameter Name="StrName" Type="String" /> 
       <asp:Parameter Name="original_StrID" Type="Int32" /> 
      </UpdateParameters> 
     </asp:SqlDataSource> 
     <br /> 
     <asp:GridView ID="GridView1" runat="server" AllowPaging="True" AllowSorting="True" AutoGenerateColumns="False" DataKeyNames="StrID" DataSourceID="SqlDataSource1"> 
      <Columns> 
       <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" /> 
       <asp:BoundField DataField="StrName" HeaderText="StrName" SortExpression="StrName" /> 
      </Columns> 
     </asp:GridView> 

    </div> 
    </form> 
</body> 
</html>

和的.aspx

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Web; 
using System.Web.UI; 
using System.Web.UI.WebControls; 
using System.Data; 
using System.Data.SqlClient; 
using System.Configuration; 


public partial class AdmAddStreet : System.Web.UI.Page 
{ 
    protected void Page_Load(object sender, EventArgs e) 
    { 

    } 

    string connectionString = ConfigurationManager.ConnectionStrings["TicketsConnectionString"].ConnectionString; 


    protected void Button1_Click1(object sender, EventArgs e) 
    { 
     try 
     { 
      DataSet ds = new DataSet(); 
      SqlConnection con = new SqlConnection(connectionString); 
      SqlCommand cmd = new SqlCommand("InsertIntoStreets", con); 
      cmd.CommandType = CommandType.StoredProcedure; 
      cmd.Parameters.Add("@StrName", SqlDbType.NVarChar).Value = txbAddress.Text; 
      cmd.Parameters["@StrName"].Value = txbAddress.Text; 
      con.Open(); 
      cmd.ExecuteNonQuery(); 
      con.Close(); 

      DisplayMessage.Text = "Record inserted."; 
      DisplayMessage.Visible = true; 
      GridView1.DataBind(); 
      txbAddress.Text = string.Empty; 
     } 
     catch 
     { 
      DisplayMessage0.Text = "Record already exist."; 
      DisplayMessage.Visible = true; 
     } 
    } 
}

你能指出我在哪裏嘗試......趕上問題，也許可能的解決辦法嗎？

來源

2013-08-20 Andrey

是否進入嘗試捕捉？你有沒有試過設置breakpooints？（你設置DisplayMessage0文本但DisplayMessage爲可見） – Sayse

你不想顯示錯誤信息，你分配給你的顯示消息變量？ – SeeSharp

作爲一般規則，您絕對不應該爲預期的程序流程使用異常 - 它們速度慢且代價高昂。相反，您應該在插入記錄之前檢查重複項。或者，根據需要使用SQL MERGE語句來執行INSERT或UPDATE。 – Keith

那麼你設置的消息，但你永遠使其可見：

DisplayMessage0.Text = "Record already exist."; 
// this is a different field ... 
DisplayMessage.Visible = true;

我相信你想要做的是：

DisplayMessage0.Text = "Record already exist."; 
DisplayMessage0.Visible = true;

注：我從你的問題理解該代碼進入catch

來源

2013-08-20 06:57:00

Thanx！我強烈請注意，我把不同的標籤:) – Andrey

@AndreyIvanov :)它發生:)很高興我能幫助。乾杯 –

嘗試此

catch 
    { 
     DisplayMessage0.Text = "Record already exist."; 
     DisplayMessage.Visible = true; 
    }

到

來源

2013-08-20 07:00:34 Amit

C＃和ASP中的異常處理.Net

回答

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