在SqlCommand SqlParameter中作为强制转换类型

Question

我正在尝试通过SqlParameter传递用户名和密码。

但是没有执行查询。

string strSQL = @"SELECT User_ID, Enabled 
              FROM User_Reg 
              WHERE Username = @paramUsername 
                AND CAST(Password AS varbinary(30)) = CAST(@paramPassword AS varbinary(30))";

objSqlCommand = new SqlCommand(strSQL, objSqlDbComm.SqlConnectionObject);
objSqlCommand.Parameters.AddWithValue("@paramUsername", txtUsername.Text);
objSqlCommand.Parameters.AddWithValue("@paramPassword", txtPassword.Text);

DataTable objDataTable = objSqlDbComm.ExecuteDataset(objSqlCommand).Tables[0];

objDataTable.Rows.Count计数为0。

Answer 1

string strSQL = @"SELECT User_ID, Enabled FROM User_Reg WHERE Username = '"+txtUsername.Text+"'AND CAST(Password AS varbinary(30)) = CAST('"+txtPassword.Text+"' AS varbinary(30))";
objSqlCommand = new SqlCommand(strSQL, objSqlDbComm.SqlConnectionObject);
objSqlCommand.ExecuteNonQuery();

Answer 2

string Query = @"SELECT User_ID, Enabled FROM User_Reg WHERE Username = '"+txtUsername.Text+"'AND CAST(Password AS varbinary(30)) = CAST('"+txtPassword.Text+"' AS varbinary(30))";
objSqlCommand = new SqlCommand(Query, objSqlDbComm.SqlConnectionObject);
objSqlCommand.ExecuteNonQuery();