SqlException未处理System.Data.dll中发生了类型为'System.Data.SqlClient.SqlException'的未处理异常

Question

我正在用C＃和SQL学习WinForms。当我执行代码时，出现此错误： “在System.Data.dll中发生了'System.Data.SqlClient.SqlException类型的未处理的异常”

代码如下：

string connetionString;
        SqlConnection cnn;
        connetionString = @"Data Source=desktop-brvgrif\sqlexpress;Integrated Security=True";
        cnn = new SqlConnection(connetionString);
        cnn.Open();

        SqlCommand command;
        SqlDataReader dataReader;
        String sql, Output = "";

        sql = "SELECT TutorialID,TutorialName from demotb";
        command = new SqlCommand(sql, cnn);
        dataReader = command.ExecuteReader();

        while(dataReader.Read())
        {
            Output = Output + dataReader.GetValue(0) + " - " + dataReader.GetValue(1) + "\n";
        }
        MessageBox.Show(Output);

        dataReader.Close();
        command.Dispose();
        cnn.Close();

Answer 1

请不要忘记在连接字符串中包含数据库名称（初始目录）。

connetionString = "Data Source=desktop-brvgrif\sqlexpress;Initial Catalog=MyDatabaseNameHere;Integrated Security=True";

Connection String Syntax