Compare data table with same column in different table vb.net - vb.net

Question

I want to create evaluation program to compare two tables (entry and validation) whether they have same data or not. The number of column two tables are same. For Example there are T_A_Entry, T_A_Val, T_B_Entry, T_B_Val, T_C_Entry, T_C_Val, etc.
I have populated all tables in database with combobox. combobox1 to select entry table, combobox2 to select validation table, combobox3 to select column (but this is optional). I can't figure out how to make comparison in each column.
See image of the tables
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
svr = TextBox1.Text
ComboBox1.Items.Clear()
If Button1.Text = " Connected " Then
Button1.Text = "Connect"
cn.Close()
Exit Sub
End If
Call conDB()
Try
cn.Open()
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
If cn.State = ConnectionState.Open Then
Button1.Text = "Connected"
comm.CommandText = "SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE='BASE TABLE' ORDER BY 'TABLE_NAME' ASC"
dr = comm.ExecuteReader
If dr.HasRows Then
ComboBox1.Items.Clear()
ComboBox2.Items.Clear()
While dr.Read()
ComboBox1.Items.Add(dr("TABLE_NAME"))
ComboBox2.Items.Add(dr("TABLE_NAME"))
End While
End If
dr.Close()
cn.Close()
Else
MessageBox.Show("Fail to Connect")
Button1.Text = "Connect"
End If
End Sub
Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged
Dim xsql As String
' mencari nama kolom tabel
xsql = " SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME= '" & ComboBox1.Text & "'"
Call conDB()
cn.Open()
comm.CommandText = xsql
dr = comm.ExecuteReader
If dr.HasRows Then
ComboBox3.Items.Clear()
While dr.Read()
ComboBox3.Items.Add(dr.Item(0))
End While
End If
dr.Close()
cn.Close()
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Me.Close()
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Call FillGrid(ComboBox1.Text, ComboBox2.Text, ComboBox3.Text)
End Sub
Private Sub FillGrid(ByVal tabelEntry As String, ByVal tabelValidasi As String, ByVal variabel As String)
Dim ds As New DataSet()
'helpp....
End Sub