Dim cnn As New SqlConnection()
  Dim cmd As SqlCommand
  Dim sName As String
  Dim rdr As SqlDataReader
  cnn.ConnectionString = CONNECTION_STRING
  cmd = New SqlCommand
  cmd.Connection = cnn
  cmd.CommandType = Data.CommandType.StoredProcedure
  cmd.CommandText = "fngetname"
  'also tried prm name = 'IDS', not '@IDS'
  cmd.Parameters.Add("@IDS", SqlDbType.Int)
  cmd.Parameters("@IDS").Value = 5
cmd.Connection.Open()
rdr = cmd.ExecuteReader()
' function is scalar but tried this way also. In any case, the reader is empty
  While rdr.Read
      sName = rdr.ToString
       frmBook.txtName.Text = sName
  End While

' by column name '
sName = rdr("ColumnNameInDatabase").Value.ToString()
' or by index '
sName = rdr(0).Value.ToString()

        sqlProcedure = "dbo.StoProName"
        Dim cmd As New SqlCommand(sqlProcedure, con)
        cmd.CommandType = CommandType.StoredProcedure
        cmd.Parameters.Add("@sUserID", SqlDbType.VarChar)
        cmd.Parameters("@sUserID").Value = txtUserName.Text

        Try
            con.Open()
            status = Convert.ToBoolean(cmd.ExecuteScalar())
        Catch ex As Exception
            Dim err As New errormsgbox
            err.errmsg = "Error reaching database. Please contact support or try again later."
            err.updateerror()
            err.ShowDialog()
            err.Dispose()
        End Try
        con.Close()

ALTER FUNCTION [dbo].[fnGetName]
(
    -- Add the parameters for the function here
    @IDS int
)
RETURNS nvarchar(75)
WITH EXECUTE AS CALLER -- tried with this commented out also
AS
BEGIN

DECLARE @FullName nvarchar(75), @Lname nvarchar(50),@Fname nvarchar(50), @PatientIDS int;

    SELECT @PatientIDS=PatientIDS, @Fname=Fname, @Lname = Lname FROM tblPatient WHERE PatientIDS = @IDS

    IF @FNAME IS NULL
        SET @FullName = @Lname
    ELSE
    SET @FullName = @Lname + ', ' + @Fname
    RETURN @FullName
END

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim strSQL As String
        Dim status
        strSQL = "dbo.fnGetName"

        conn = New SqlConnection
        conn.ConnectionString = appConn
        Dim cmd As New SqlCommand(strSQL, conn)

        cmd.CommandType = CommandType.StoredProcedure
        cmd.Parameters.Add("@IDS", SqlDbType.Int)
        cmd.Parameters("@IDS").Value = 5 ' txtUserName.Text

        Try
            conn.Open()
            status = Convert.ToString(cmd.ExecuteScalar())
            Me.TextBox1.Text = status

        Catch exp As Exception
            MessageBox.Show(exp.Message, Me.Text, MessageBoxButtons.OK, MessageBoxIcon.Stop)
        Finally
            conn.Close()
        End Try
    End Sub
    

ALTER PROCEDURE procGetName
@IDS int, @ReturnName nvarchar(75) OUTPUT
AS

DECLARE @FullName nvarchar(75),@Lname nvarchar(50),@Fname nvarchar(50), @PatientIDS int;

    SELECT @PatientIDS=PatientIDS, @Fname=Fname, @Lname = Lname FROM tblPatient WHERE PatientIDS = @IDS

    IF @FNAME IS NULL
        SET @FullName = @Lname
    ELSE
    SET @FullName = @Lname + ', ' + @Fname
set @ReturnName = @Fullname
RETURN

'And the code
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim cnn As New SqlConnection()
        Dim cmd As New SqlCommand
        Dim result
        Dim CONNECTION_STRING As String = "Data Source=PMK-DC2;Initial Catalog=PB.1.0_be;Integrated Security=True"
        Try


            cnn.ConnectionString = CONNECTION_STRING
            With cmd
                .CommandType = Data.CommandType.StoredProcedure
                .CommandText = "procGetname"
                .Parameters.AddWithValue("@IDS", 5)
                .Parameters.Add("@ReturnName", SqlDbType.NVarChar, 75)
                .Parameters(0).Direction = ParameterDirection.Input
                .Parameters(1).Direction = ParameterDirection.Output

                .Connection = cnn
                .Connection.Open()
            End With
            'frmBook.txtName.Text = cmd.ExecuteScalar.ToString
           'NOTHING IS RETURNED HERE - 'RESULT' IS AN EMPTY STRING
            result = cmd.ExecuteScalar
            Debug.Print(result)
        Catch ex As Exception
            MsgBox(ex.ToString)
        Finally
            cmd.Connection.Close()
            cmd = Nothing
        End Try
    End Sub