我想从SQLite数据库[C#]中获取单个值

我试图从sqlite数据库中获取单个值，但遇到了错误

所以我可以对这个值做一些操作或者检查它

dbConnection StartConn = new dbConnection();
            SQLiteConnection MyConnetion = StartConn.GetConnection();

            SQLiteCommand Cm = new SQLiteCommand(" select * from Users where user_username = '" + txtBxUserName.Text + "' and user_password = '" + txtBxPassword.Text + "'", MyConnetion);

            MyConnetion.Open();
            SQLiteDataReader dr = Cm.ExecuteReader();
            dr.Read();

            int count = Convert.ToInt32(Cm.ExecuteScalar());

            if (count != 0)
            {
                globalVariables.userFullName = dr["user_name"].ToString();
                globalVariables.appLoginUser = dr["user_username"].ToString();
                globalVariables.appPasswordUser = dr["user_password"].ToString();
                globalVariables.userPermissions = dr["user_permissions"].ToString();

                mainForm newMainForm = new mainForm();
                newMainForm.Show();
                this.Hide();

                MyConnetion.Close();

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您的dtareader没有行，这会导致错误。试着这样做：

if(dr.Read())
{
    // rest of your code
}

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globalVariables

似乎为空。此上下文中是否存在

globalVariables

？