C# 未处理的参数异常

Question

我遇到错误，这是我的代码。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace dbgen
{
       static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            using(SqlConnection conn = new SqlConnection())
            {
                    conn.ConnectionString = "Server=DESKTOP-7AN9GF5;Database=Velocity;Trusted_Connection=true";
                    // using the code here...
                    conn.ConnectionString = "connection_string";
                    conn.Open();

                using (SqlConnection connection = new SqlConnection(
                "Integrated Security=SSPI;Initial Catalog=Northwind"))
                {
                    connection.Open();
                    // Pool A is created.
                }

                using (SqlConnection connection = new SqlConnection(
                "Integrated Security=SSPI;Initial Catalog=pubs"))
                {
                    connection.Open();
                    // Pool B is created because the connection strings differ.
                }

                using (SqlConnection connection = new SqlConnection(
                "Integrated Security=SSPI;Initial Catalog=Northwind"))
                {
                    connection.Open();
                    // The connection string matches pool A.
                }
            }

            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new mainform());
        }
}
       }

我正在使用 Visual Studio 2013 将数据库连接到 SQL Server Express 上的 Velocity [数据库名称]。这是错误的屏幕截图。

ERROR SCREENSHOT

谢谢你的帮助。

Answer 1

您必须为 "conn.ConnectionString" 分配正确的连接字符串。 "connection_string" 不是连接字符串，应该像 "Server=xxx;Database=xxx;".

Answer 2

您的连接字符串格式不正确。为什么不使用 :

conn.ConnectionString = "Server=DESKTOP-7AN9GF5;Database=Velocity;Trusted_Connection=true";

C# 未处理的参数异常

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