Compare Two DataTable and Remove (Delete) duplicate record using C# and VB.Net in Windows Application

Hi ryutenkan,

Check this example. Now please take its reference and correct your code.

Code

C#

private void btnRemove_Click(object sender, EventArgs e)
{
    // Get DataTables from Access Database.
    DataTable dt1 = new DataTable();
    dt1.Columns.AddRange(new DataColumn[3] { new DataColumn("Id", typeof(int)),
                new DataColumn("Name", typeof(string)),
                new DataColumn("Country",typeof(string)) });
    dt1.Rows.Add(1, "John Hammond", "United States");
    dt1.Rows.Add(3, "Suzanne Mathews", "France");
    dt1.Rows.Add(4, "Robert Schidner", "Russia");

    DataTable dt2 = new DataTable();
    dt2.Columns.AddRange(new DataColumn[3] { new DataColumn("Id", typeof(int)),
                new DataColumn("Name", typeof(string)),
                new DataColumn("Country",typeof(string)) });
    dt2.Rows.Add(1, "John Hammond", "United States");
    dt1.Rows.Add(2, "Mudassar Khan", "India");
    dt2.Rows.Add(3, "Suzanne Mathews", "France");
    dt2.Rows.Add(5, "Robert Schidner", "Russia");

    List<DataRow> common = (from r1 in dt1.AsEnumerable()
                            join r2 in dt2.AsEnumerable() on r1["Id"] equals r2["Id"]
                            select r1).ToList();

    foreach (DataRow dr in common)
    {
        for (int i = dt2.Rows.Count - 1; i >= 0; i--)
        {
            DataRow drDelete = dt2.Rows[i];
            if (dr["Id"].ToString() == dt2.Rows[i]["Id"].ToString()
                && dr["Name"].ToString() == dt2.Rows[i]["Name"].ToString()
                && dr["Country"].ToString() == dt2.Rows[i]["Country"].ToString())
            {
                drDelete.Delete();
            }
        }
        dt2.AcceptChanges();
    }

    dataGridView1.DataSource = dt2;
}

VB.Net

Private Sub btnRemove_Click(sender As System.Object, e As System.EventArgs) Handles btnRemove.Click
    ' Get DataTables from Access Database.
    Dim dt1 As DataTable = New DataTable()
    dt1.Columns.AddRange(New DataColumn(2) {
                         New DataColumn("Id", GetType(Integer)),
                         New DataColumn("Name", GetType(String)),
                         New DataColumn("Country", GetType(String))})
    dt1.Rows.Add(1, "John Hammond", "United States")
    dt1.Rows.Add(3, "Suzanne Mathews", "France")
    dt1.Rows.Add(4, "Robert Schidner", "Russia")
    Dim dt2 As DataTable = New DataTable()
    dt2.Columns.AddRange(New DataColumn(2) {
                         New DataColumn("Id", GetType(Integer)),
                         New DataColumn("Name", GetType(String)),
                         New DataColumn("Country", GetType(String))})
    dt2.Rows.Add(1, "John Hammond", "United States")
    dt1.Rows.Add(2, "Mudassar Khan", "India")
    dt2.Rows.Add(3, "Suzanne Mathews", "France")
    dt2.Rows.Add(5, "Robert Schidner", "Russia")
    Dim common As List(Of DataRow) = (From r1 In dt1.AsEnumerable() _
                                      Join r2 In dt2.AsEnumerable() On r1("Id") Equals r2("Id") _
                                      Select r1).ToList()
    For Each dr As DataRow In common
        For i As Integer = dt2.Rows.Count - 1 To 0 Step -1
            Dim drDelete As DataRow = dt2.Rows(i)
            If dr("Id").ToString() = dt2.Rows(i)("Id").ToString() _
                AndAlso dr("Name").ToString() = dt2.Rows(i)("Name").ToString() _
                AndAlso dr("Country").ToString() = dt2.Rows(i)("Country").ToString() Then
                drDelete.Delete()
            End If
        Next
        dt2.AcceptChanges()
    Next
    dataGridView1.DataSource = dt2
End Sub

Screenshot