Reference to a non-shared member requires an object reference

Question

I am creating window forms in Visual basic and each form has different names. As I try to call one form from another form I am getting an error: "Reference to a non-shared member requires an object reference" and I do not know how to resolve this. Below is a copy of one of my forms where I am getting this error.

Imports System.Data.SqlClient
Imports System.Data
Imports System.Windows.Forms
Imports System.Drawing

Public Class CustomerRecords

    Private Sub btnClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
        Me.Close()
    End Sub

    Public Sub GetData()
        Try
            conn = New SqlConnection(cs)
            conn.Open()
            cmd = New SqlCommand("SELECT RTRIM(ID),RTRIM(CustomerID),RTRIM([Name]),RTRIM(Gender), RTRIM(Address),RTRIM(City),RTRIM(State),RTRIM(ZipCode), RTRIM(ContactNo), RTRIM(EmailID),RTRIM(Remarks),Photo from Customer where CustomerType='Regular' order by name", conn)
            rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection)
            dgw.Rows.Clear()
            While (rdr.Read() = True)
                dgw.Rows.Add(rdr(0), rdr(1), rdr(2), rdr(3), rdr(4), rdr(5), rdr(6), rdr(7), rdr(8), rdr(9), rdr(10), rdr(11))
            End While
            conn.Close()
        Catch ex As Exception
            MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
    End Sub

    Private Sub frmLogs1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        GetData()
    End Sub

    Private Sub btnClose_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClose.Click
        Me.Close()
    End Sub

    Private Sub dgw_MouseClick(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles dgw.MouseClick
        Try
            If dgw.Rows.Count > 0 Then
                Dim dr As DataGridViewRow = dgw.SelectedRows(0)

                If lblSet.Text = "Billing" Then
                    Show()
                    Me.Hide()
'Error Starts here.
                    Billings.txtCID.Text = dr.Cells(0).Value.ToString()
                    Billings.txtCustomerID.Text = dr.Cells(1).Value.ToString()
                    Billings.txtCustomerName.Text = dr.Cells(2).Value.ToString()
                    Billings.txtContactNo.Text = dr.Cells(8).Value.ToString()
                    Billings.txtCustomerName.ReadOnly = True
                    Billings.txtContactNo.ReadOnly = True
                    lblSet.Text = ""
                End If
                If lblSet.Text = "Quotation" Then
                    Quotation.Show()
                    Me.Hide()
                    Quotation.txtCID.Text = dr.Cells(0).Value.ToString()
                    Quotation.txtCustomerID.Text = dr.Cells(1).Value.ToString()
                    Quotation.txtCustomerName.Text = dr.Cells(2).Value.ToString()
                    Quotation.txtContactNo.Text = dr.Cells(8).Value.ToString()
                    Quotation.txtCustomerName.ReadOnly = True
                    Quotation.txtContactNo.ReadOnly = True
                    lblSet.Text = ""
                End If
            End If
        Catch ex As Exception
            MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
    End Sub

    Private Sub dgw_RowPostPaint(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewRowPostPaintEventArgs) Handles dgw.RowPostPaint
        Dim strRowNumber As String = (e.RowIndex + 1).ToString()
        Dim size As SizeF = e.Graphics.MeasureString(strRowNumber, Me.Font)
        If dgw.RowHeadersWidth < Convert.ToInt32((size.Width + 20)) Then
            dgw.RowHeadersWidth = Convert.ToInt32((size.Width + 20))
        End If
        Dim b As Brush = SystemBrushes.ControlText
        e.Graphics.DrawString(strRowNumber, Me.Font, b, e.RowBounds.Location.X + 15, e.RowBounds.Location.Y + ((e.RowBounds.Height - size.Height) / 2))

    End Sub

    Private Sub txtCustomerName_TextChanged(sender As System.Object, e As System.EventArgs) Handles txtCustomerName.TextChanged
        Try
            conn = New SqlConnection(cs)
            conn.Open()
            cmd = New SqlCommand("SELECT RTRIM(ID),RTRIM(CustomerID),RTRIM([Name]),RTRIM(Gender), RTRIM(Address),RTRIM(City),RTRIM(State),RTRIM(ZipCode), RTRIM(ContactNo), RTRIM(EmailID),RTRIM(Remarks),Photo from Customer where CustomerType='Regular' and name like '%" & txtCustomerName.Text & "%' order by name", conn)
            rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection)
            dgw.Rows.Clear()
            While (rdr.Read() = True)
                dgw.Rows.Add(rdr(0), rdr(1), rdr(2), rdr(3), rdr(4), rdr(5), rdr(6), rdr(7), rdr(8), rdr(9), rdr(10), rdr(11))
            End While
            conn.Close()
        Catch ex As Exception
            MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
    End Sub

    Private Sub txtCity_TextChanged(sender As System.Object, e As System.EventArgs) Handles txtCity.TextChanged
        Try
            conn = New SqlConnection(cs)
            conn.Open()
            cmd = New SqlCommand("SELECT RTRIM(ID),RTRIM(CustomerID),RTRIM([Name]),RTRIM(Gender), RTRIM(Address),RTRIM(City),RTRIM(State),RTRIM(ZipCode), RTRIM(ContactNo), RTRIM(EmailID),RTRIM(Remarks),Photo from Customer where CustomerType='Regular' and City like '%" & txtCity.Text & "%' order by city", conn)
            rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection)
            dgw.Rows.Clear()
            While (rdr.Read() = True)
                dgw.Rows.Add(rdr(0), rdr(1), rdr(2), rdr(3), rdr(4), rdr(5), rdr(6), rdr(7), rdr(8), rdr(9), rdr(10), rdr(11))
            End While
            conn.Close()
        Catch ex As Exception
            MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
    End Sub

    Sub Reset()
        txtCustomerName.Text = ""
        txtContactNo.Text = ""
        txtCity.Text = ""
        GetData()
    End Sub

    Private Sub btnReset_Click(sender As System.Object, e As System.EventArgs) Handles btnReset.Click
        Reset()
    End Sub

    Private Sub txtContactNo_TextChanged(sender As System.Object, e As System.EventArgs) Handles txtContactNo.TextChanged
        Try
            conn = New SqlConnection(cs)
            conn.Open()
            cmd = New SqlCommand("SELECT RTRIM(ID),RTRIM(CustomerID),RTRIM([Name]),RTRIM(Gender), RTRIM(Address),RTRIM(City),RTRIM(State),RTRIM(ZipCode), RTRIM(ContactNo), RTRIM(EmailID),RTRIM(Remarks),Photo from Customer where CustomerType='Regular' and ContactNo like '%" & txtContactNo.Text & "%' order by city", conn)
            rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection)
            dgw.Rows.Clear()
            While (rdr.Read() = True)
                dgw.Rows.Add(rdr(0), rdr(1), rdr(2), rdr(3), rdr(4), rdr(5), rdr(6), rdr(7), rdr(8), rdr(9), rdr(10), rdr(11))
            End While
            conn.Close()
        Catch ex As Exception
            MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
    End Sub

    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Customer.lblUser.Text = lblUser.Text
        Customer.Reset()
        Customer.Reset()
        ShowDialog()
    End Sub
    Private Sub frmCustomerRecords1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    End Sub
End Class

Answer 1

You need to supply this form with an instance of the other form.

When you create an instance of the CustomerRecords form in code, you can supply it with an existing instance of another form. There are a number of ways to do that, from exposing a property on CustomerRecords to creating a constructor method (Sub New) which takes an instance of the other form as a parameter.  One way or another you need to supply CustomerRecords with an instance of the Billing and/or Quotations classes.

There are lots of examples of this kind of thing on these forums.

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Reed Kimble - "When you do things right, people won't be sure you've done anything at all"

Answer 2

Your style of handling a database is very outdated. It means that you have 90% more code than is needed and therefore 90% more chance on an error and need 90% more time to find those errors. 

Use dataadapters, linq to sql or the entitityframework.

https://msdn.microsoft.com/en-us/library/bb386876(v=vs.100).aspx

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