如何将存储过程中的值从SQL返回到C＃

Question

So I am storing a value which is the student reference number which I have done, not I need to return the value from my ID and my DateTime in textbox2 and textbox 3. Whilst inputting and executing the procedure.

using (SqlConnection con = new *****))
{
    SqlCommand cmd = con.CreateCommand();
    cmd.CommandText = "Exams_BagCheck_ScanIn";
    {
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.Parameters.AddWithValue("@StudentReference", SqlDbType.VarChar).Value = textBox1.Text;
        cmd.Parameters.AddWithValue("@ID", SqlDbType.Int).Direction = ParameterDirection.ReturnValue;
        con.Open();
        cmd.ExecuteNonQuery();

The procedure

USE [IFCustom]
GO

DECLARE @return_value Int

EXEC    @return_value = [dbo].[Exams_BagCheck_ScanIn]
        @StudentReference = N'1'

SELECT  @return_value as 'Return Value'

GO

Answer 1

Your procedure returns nothing, you need to remove:

SELECT @return_value as 'Return Value'

And instead:

RETURN @return_value

(If you wanted to select then .ExecuteScalar() would return the value)

Answer 2

If you just returning a single value then you can use

this:

string some_value = cmd.ExecuteScalar().ToString(); // if it is string

OR

Object some_value = cmd.ExecuteScalar(); // convert it to its repective type.

in place of

cmd.ExecuteNonQuery();

// some_value will contain the value you selected as SELECT @return_value in procedure.