当执行SqlCommand.ExecuteScalar（）时，Visual Studio停止调试

Question

I have this code in my application

SqlConnection sqlConnection1 = new SqlConnection(connectionString);

SqlCommand cmd = new SqlCommand();
cmd.CommandType = System.Data.CommandType.Text;

sqlConnection1.Open();

cmd.CommandText = "SELECT S2 FROM CDUSR WHERE N100 = " + N100.ToString()  ;

var HashStr = cmd.ExecuteScalar();
sqlConnection1.Close();

When I reach at the line

var HashStr = cmd.ExecuteScalar();

Visual Studio 2015 stops debugging my application without any error.

connectionString contains a valid connection string (I have tested)

This query SELECT S2 FROM CDUSR WHERE N100 = 6369 executes successfully in SSMS.

I want to know what the problem is. S2 contains the following string:

a4sd4545ag5645sdfa55sdf45fv5er5cfvg5s45

Answer 1

Are you using the correct constructor for the SqlCommand? It seems to me that you are atleast missing:

cmd.Connection = sqlConnection1

You might as well do that in the constructor when you create the command:

SqlCommand cmd = new SqlCommand("SELECT S2 FROM CDUSR WHERE N100 = " + N100.ToString()), sqlConnection1)

a using block would be nice as well:

using(SqlCommand cmd = new SqlCommand(blah blah)) { cmd.ExecuteScalar; }

Answer 2

我想Visual Studio会停止调试，因为您的代码会引发异常（您的SqlCommand与您使用的SqlConnection没有关联）...也许您在“异常设置”中禁用了“公共语言运行时异常”，所以您实际上看不到引发异常...