抛出异常：System.Data.dll 中的“System.ArgumentException”

Question

我尝试了很多方法来解决问题，但没有找到正确的答案。当点击保存按钮时，会出现以下消息；

抛出异常：System.Data.dll 中的“System.ArgumentException”

并突出显示该行

public static SqlConnection con = new SqlConnection(s);

这里是详细代码。

Connection.cs 文件

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;
using System.Data.SqlClient;
using System.Data;

namespace IMS
{
    class Connection
    {
        private static string s = File.ReadAllText(Application.StartupPath + "\\Connect.txt");
        public static SqlConnection con = new SqlConnection(s);
    }
}

我在哪里编写插入代码以在表中插入数据

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;
using System.Data.SqlClient;
using System.Data;

namespace IMS
{
    class insertion
    {
        public void InsertUser(string name, string username, string password, string email, Int16 status)
        {
            try
            {
                SqlCommand cmd = new SqlCommand("sy_InsertUser", Connection.con);
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.Parameters.AddWithValue("@name", name);
                cmd.Parameters.AddWithValue("@username", username);
                cmd.Parameters.AddWithValue("@password", password);
                cmd.Parameters.AddWithValue("@email", email);
                cmd.Parameters.AddWithValue("@status", status);
                Connection.con.Open();
                if (cmd.ExecuteNonQuery()>= 1)
                {
                    mainclass.ShowSucsMsg("User Added Successfuly");
                }
                Connection.con.Close();
            }
            catch (Exception ex)
            {
                Dashborad.ShowExpMsg(ex);
            }
        }
    }
}

数据保存按钮代码

 public override void savebtn_Click(object sender, EventArgs e)
        {
            insertion obj = new insertion();
            obj.InsertUser(usnametxt.Text, usUsernametxt.Text, usPasswordtxt.Text, usEmailtxt.Text, Status);
        }

App.Cofig

 <appSettings>
    <add key="" value="\\Connect.txt" />
  </appSettings>

Answer 1

您不应将连接保持为静态。你应该这样使用连接：

using (var connection = new SqlConnection(
               connectionString))
    {
                var command = new SqlCommand("sy_InsertUser", connection);
                command.CommandType = CommandType.StoredProcedure;
                command.Parameters.AddWithValue("@name", name);
                command.Parameters.AddWithValue("@username", username);
                command.Parameters.AddWithValue("@password", password);
                command.Parameters.AddWithValue("@email", email);
                command.Parameters.AddWithValue("@status", status);
                command.connection.Open();
                if (command.ExecuteNonQuery()>= 1)
                {
                    mainclass.ShowSucsMsg("User Added Successfuly");
                }
       
    }