Compare and Delete duplicate Records from two DataTables in ASP.Net

Hi paulrajmca,

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

HTML

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="UserId" HeaderText="UserId" />
        <asp:BoundField DataField="UserName" HeaderText="UserName" />
    </Columns>
</asp:GridView>
<br />
<asp:GridView ID="GridView2" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="UserId" HeaderText="UserId" />
        <asp:BoundField DataField="UserName" HeaderText="UserName" />
    </Columns>
</asp:GridView>
<br />
<asp:GridView ID="GridView3" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="UserId" HeaderText="UserId" />
        <asp:BoundField DataField="UserName" HeaderText="UserName" />
    </Columns>
</asp:GridView>

Namespaces

C#

using System.Data;

VB.Net

Imports System.Data

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        DataTable dt1 = new DataTable();
        dt1.Columns.AddRange(new DataColumn[2] { new DataColumn("UserId"), new DataColumn("UserName") });
        dt1.Rows.Add("01", "Test Series 01");
        dt1.Rows.Add("02", "Test Series 02");
        dt1.Rows.Add("03", "Test Series 03");
        dt1.Rows.Add("04", "Test Series 04");
        this.GridView1.DataSource = dt1;
        this.GridView1.DataBind();

        DataTable dt2 = new DataTable();
        dt2.Columns.AddRange(new DataColumn[2] { new DataColumn("UserId"), new DataColumn("UserName") });
        dt2.Rows.Add("01", "Test Series 01");
        dt2.Rows.Add("02", "Test Series 08");
        dt2.Rows.Add("03", "Test Series 03");
        this.GridView2.DataSource = dt2;
        this.GridView2.DataBind();

        DataTable dt3 = dt1.Copy();
        foreach (DataRow row1 in dt2.Rows)
        {
            bool isRecordExist = false;
            foreach (DataRow row2 in dt1.Rows)
            {
                if (row1["UserId"] == row2["UserId"] && row1["UserName"] == row2["UserName"])
                {
                    isRecordExist = true;
                }
            }
            if (!isRecordExist)
            {
                dt3.ImportRow(row1);
            }
        }

        this.GridView3.DataSource = dt3;
        this.GridView3.DataBind();
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not IsPostBack Then
        Dim dt1 As DataTable = New DataTable()
        dt1.Columns.AddRange(New DataColumn(1) {New DataColumn("UserId"), New DataColumn("UserName")})
        dt1.Rows.Add("01", "Test Series 01")
        dt1.Rows.Add("02", "Test Series 02")
        dt1.Rows.Add("03", "Test Series 03")
        dt1.Rows.Add("04", "Test Series 04")
        Me.GridView1.DataSource = dt1
        Me.GridView1.DataBind()
        Dim dt2 As DataTable = New DataTable()
        dt2.Columns.AddRange(New DataColumn(1) {New DataColumn("UserId"), New DataColumn("UserName")})
        dt2.Rows.Add("01", "Test Series 01")
        dt2.Rows.Add("02", "Test Series 08")
        dt2.Rows.Add("03", "Test Series 03")
        Me.GridView2.DataSource = dt2
        Me.GridView2.DataBind()
        Dim dt3 As DataTable = dt1.Copy()

        For Each row1 As DataRow In dt2.Rows
            Dim isRecordExist As Boolean = False

            For Each row2 As DataRow In dt1.Rows

                If row1("UserId") = row2("UserId") AndAlso row1("UserName") = row2("UserName") Then
                    isRecordExist = True
                End If
            Next

            If Not isRecordExist Then
                dt3.ImportRow(row1)
            End If
        Next

        Me.GridView3.DataSource = dt3
        Me.GridView3.DataBind()
    End If
End Sub

Screenshot