Error: The member codeproduct of type Stocks cannot be used as a parameter value

Hi kana250688,

Refer below sample code.

VB.Net

Imports System.Data.OleDb
Imports Dapper

Public Class Form1
    Public _myTable As New DataTable()
    Protected Overrides Sub OnLoad(e As EventArgs)
        MyBase.OnLoad(e)
        _myTable.Columns.AddRange({
        New DataColumn("CodeProduct", GetType(String)),
        New DataColumn("CatProd", GetType(String)),
        New DataColumn("Barcode", GetType(String)),
        New DataColumn("ColorCode", GetType(String))})
    End Sub
    Private Function parseBarcodeScan(input As String) As List(Of String)
        Return input.Split({","}, StringSplitOptions.RemoveEmptyEntries).Select(Function(s) s.Trim()).ToList()
    End Function
    Private Sub BtxtBarcode_KeyPress(sender As Object, e As KeyPressEventArgs) Handles BtxtBarcode.KeyPress
        If e.KeyChar = Convert.ToChar(Keys.Enter) Then
            AddEntry()
        End If
    End Sub
    Private Sub AddEntry()
        Dim items = parseBarcodeScan(BtxtBarcode.Text)
        Try
            Dim sservice = New Stockservice()
            Dim Qty_Stocks = New Stocks With {
                 .CodeProduct = items(0),
                 .CatProd = items(1),
                 .Barcode = items(2),
                 .Colorcode = items(3)}
            Dim checkitem = sservice.GetByQrSplit(Qty_Stocks)
            Dim checkstock As Integer = sservice.GetByQrSplitbysum(Qty_Stocks)
            If checkitem Is Nothing Then
                MessageBox.Show("Unknown item!")
                BtxtBarcode.Clear()
                Return
            End If
            If checkstock < 0 Then
                MessageBox.Show("item no stock!")
                BtxtBarcode.Clear()
                Return
            End If
            ' Where does _BBarcode come from?
            _myTable.Rows.Add(items(0), items(1), items(2), items(3))
            DataGridView1.DataSource = _myTable
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
    End Sub
End Class
Public Class Stocks
    Public Property CodeProduct() As String
    Public Property CatProd() As String
    Public Property Barcode() As String
    Public Property Colorcode() As String
    Public Property Qty_Stock() As Integer
End Class
Public Class Stockservice
    Public Function GetOledbConnectionString() As String
        Return "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\Stocks.accdb;Persist Security Info=False;"
    End Function
    Private ReadOnly _conn As OleDbConnection
    Private _connectionString As String = GetOledbConnectionString()
    Public Sub New()
        _conn = New OleDbConnection(_connectionString)
    End Sub
    Public Function GetByQrSplit(ByVal code As Stocks) As Stocks
        Dim sql = "SELECT * FROM Stocks WHERE CodeProduct = @CodeProduct and CatProd = @CatProd and Barcode = @Barcode and Colorcode = @Colorcode"
        Using _conn = New OleDbConnection(GetOledbConnectionString())
            Dim dynamicParameters As DynamicParameters = New DynamicParameters()
            ' Adding Input parameters.
            dynamicParameters.Add("@CodeProduct", code.CodeProduct)
            dynamicParameters.Add("@CatProd", code.CatProd)
            dynamicParameters.Add("@Barcode", code.Barcode)
            dynamicParameters.Add("@Colorcode", code.Colorcode)
            Return _conn.Query(Of Stocks)(sql, dynamicParameters).FirstOrDefault()
        End Using
    End Function
    Public Function GetByQrSplitbysum(ByVal code As Stocks) As Integer
        Dim qtyStock = "SELECT sum(Qty_Stock) AS [Qty_Stock] FROM Stocks WHERE CodeProduct = @CodeProduct and CatProd = @CatProd and Barcode = @Barcode and Colorcode = @Colorcode"
        Dim checkitem As Integer = 0
        Using _conn = New OleDbConnection(GetOledbConnectionString())
            Dim dynamicParameters As DynamicParameters = New DynamicParameters()
            ' Adding Input parameters.
            dynamicParameters.Add("@CodeProduct", code.CodeProduct)
            dynamicParameters.Add("@CatProd", code.CatProd)
            dynamicParameters.Add("@Barcode", code.Barcode)
            dynamicParameters.Add("@Colorcode", code.Colorcode)
            Dim o As Object = _conn.ExecuteScalar(qtyStock, dynamicParameters)
            If o IsNot Nothing Then
                qtyStock = Convert.ToInt32(o)
            End If
        End Using
        Return checkitem
    End Function
End Class

Screenshot