How to insert DataList checked item into GridView using C# and VB.Net in ASP.Net

Hi khaled2016,

I have created sample code which full fill your requirement.

HTML

<div>
    <asp:DataList ID="DataList1" runat="server">
        <ItemTemplate>
            <asp:CheckBox ID="CheckBox1" OnCheckedChanged="OnChange" AutoPostBack="true" runat="server" />
            <br />
            person_no:
            <asp:Label ID="personnoLabel" runat="server" Text='<%# Eval("person_no") %>' />
            <br />
            person_name:
            <asp:Label ID="nameLabel" runat="server" Text='<%# Eval("person_name") %>' />
            <br />
            Country_no:
            <asp:Label ID="countrynoLabel" runat="server" Text='<%# Eval("Country_no") %>' />
            <br />
        </ItemTemplate>
    </asp:DataList>
    <br />
    <asp:GridView ID="gvDetails" runat="server" />
</div>

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        this.GetData();
        this.DummyDataTable();
    }
}

private void DummyDataTable()
{
    DataTable dt = new DataTable();
    dt.Columns.Add("PersonNo");
    dt.Columns.Add("PersonName");
    dt.Columns.Add("Country");
    ViewState["CheckedData"] = dt;
}

private void GetData()
{
    DataTable dt = new DataTable();
    dt.Columns.Add("person_no");
    dt.Columns.Add("person_name");
    dt.Columns.Add("Country_no");
    dt.Rows.Add("1", "PETER", "2514");
    dt.Rows.Add("2", "John", "21414");
    dt.Rows.Add("3", "Maria", "82947");
    dt.Rows.Add("4", "Mahi", "251744");
    DataList1.DataSource = dt;
    DataList1.DataBind();
}


protected void OnChange(object sender, EventArgs e)
{
    DataTable checkeddt = (DataTable)ViewState["CheckedData"];
    DataListItem item = (sender as CheckBox).NamingContainer as DataListItem;
    string personNo = (item.FindControl("personnoLabel") as Label).Text;
    string personName = (item.FindControl("nameLabel") as Label).Text;
    string country = (item.FindControl("countrynoLabel") as Label).Text;

    if ((item.FindControl("CheckBox1") as CheckBox).Checked)
    {
        checkeddt.Rows.Add(personNo, personName, country);
        this.GetcheckedDetails();
    }
    else
    {
        this.DummyDataTable();
        DataTable dt = (DataTable)ViewState["CheckedData"];
        foreach (DataRow row in checkeddt.Rows)
        {
            string personId = row["PersonNo"].ToString();
            if (personId != personNo)
            {
                dt.Rows.Add(row["PersonNo"].ToString(), row["PersonName"].ToString(), row["Country"].ToString());
            }
        }

        this.GetcheckedDetails();
    }
}

private void GetcheckedDetails()
{
    DataTable checkeddt = (DataTable)ViewState["CheckedData"];
    gvDetails.DataSource = checkeddt;
    gvDetails.DataBind();
}

Vb.net

Protected Sub Page_Load(sender As Object, e As EventArgs)
	If Not IsPostBack Then
		Me.GetData()
		Me.DummyDataTable()
	End If
End Sub

Private Sub DummyDataTable()
	Dim dt As New DataTable()
	dt.Columns.Add("PersonNo")
	dt.Columns.Add("PersonName")
	dt.Columns.Add("Country")
	ViewState("CheckedData") = dt
End Sub

Private Sub GetData()
	Dim dt As New DataTable()
	dt.Columns.Add("person_no")
	dt.Columns.Add("person_name")
	dt.Columns.Add("Country_no")
	dt.Rows.Add("1", "PETER", "2514")
	dt.Rows.Add("2", "John", "21414")
	dt.Rows.Add("3", "Maria", "82947")
	dt.Rows.Add("4", "Mahi", "251744")
	DataList1.DataSource = dt
	DataList1.DataBind()
End Sub


Protected Sub OnChange(sender As Object, e As EventArgs)
	Dim checkeddt As DataTable = DirectCast(ViewState("CheckedData"), DataTable)
	Dim item As DataListItem = TryCast(TryCast(sender, CheckBox).NamingContainer, DataListItem)
	Dim personNo As String = TryCast(item.FindControl("personnoLabel"), Label).Text
	Dim personName As String = TryCast(item.FindControl("nameLabel"), Label).Text
	Dim country As String = TryCast(item.FindControl("countrynoLabel"), Label).Text

	If TryCast(item.FindControl("CheckBox1"), CheckBox).Checked Then
		checkeddt.Rows.Add(personNo, personName, country)
		Me.GetcheckedDetails()
	Else
		Me.DummyDataTable()
		Dim dt As DataTable = DirectCast(ViewState("CheckedData"), DataTable)
		For Each row As DataRow In checkeddt.Rows
			Dim personId As String = row("PersonNo").ToString()
			If personId <> personNo Then
				dt.Rows.Add(row("PersonNo").ToString(), row("PersonName").ToString(), row("Country").ToString())
			End If
		Next

		Me.GetcheckedDetails()
	End If
End Sub

Private Sub GetcheckedDetails()
	Dim checkeddt As DataTable = DirectCast(ViewState("CheckedData"), DataTable)
	gvDetails.DataSource = checkeddt
	gvDetails.DataBind()
End Sub

Screenshot