C＃和ASP .Net中的异常处理

Question

I have page and SQL DB behind SQL table do not allowed duplicate names for addresses. 我在SQL表后面有页面和SQL DB，不允许地址重复名称。 I connect it to db and trying to implement try catch stamen it is working but fore some reason doesn't want to show error message 我将其连接到db并尝试实现try catch stamen，它正在工作，但是由于某些原因不想显示错误消息

HTML 的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>

and .aspx 和.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;
        }
    }
}

Can you please point me where is the problem in try...catch, and maybe possible solution for it? 能否请您指出try ... catch中的问题所在，也许是可能的解决方案？

Answer 1

Well you're setting the message but you're never making it visible: 好吧，您正在设置消息，但从未使它可见：

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

What I believe you want to do is: 我相信您想做的是：

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

Note: I understood from your question that the code enters the catch 注意：我从您的问题中了解到代码进入了catch

Answer 2

Try this 尝试这个

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

to 至

catch(Exception ex)
    {
        DisplayMessage0.Text = "Record already exist.";
       DisplayMessage0.Visible = true;
    }

C＃和ASP .Net中的异常处理

问题描述

2 个解决方案

解决方案1
4 已采纳 2013-08-20 06:57:00

解决方案2
1 2013-08-20 07:00:34

C＃和ASP .Net中的异常处理

问题描述

2 个解决方案

解决方案1 4 已采纳 2013-08-20 06:57:00

解决方案2 1 2013-08-20 07:00:34

解决方案1
4 已采纳 2013-08-20 06:57:00

解决方案2
1 2013-08-20 07:00:34