Filter ASP.Net GridView based on date selection from Ajax CalenderExtender using C# and VB.Net

Hi democloud,

Please refer below sample and according to code change your code.

HTML

<cc1:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server">
</cc1:ToolkitScriptManager>
<asp:TextBox ID="txtDate" runat="server" AutoPostBack="true" OnTextChanged="GetData"></asp:TextBox>
<asp:ImageButton ID="imgPopup" ImageUrl="~/images/Calendar.png" ImageAlign="Bottom"
    runat="server" />
<cc1:CalendarExtender ID="Calendar1" PopupButtonID="imgPopup" runat="server" TargetControlID="txtDate"
    Format="dd/MM/yyyy">
</cc1:CalendarExtender>
<asp:GridView ID="gvDates" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="Staff Name" HeaderText="Staff Name" />
        <asp:BoundField DataField="Client Name" HeaderText="Client Name" />
        <asp:BoundField DataField="date1" HeaderText="date1" DataFormatString="{0:dd/MM/yyyy}" />
        <asp:BoundField DataField="date2" HeaderText="date2" DataFormatString="{0:dd/MM/yyyy}" />
        <asp:BoundField DataField="date3" HeaderText="date3" DataFormatString="{0:dd/MM/yyyy}" />
    </Columns>
</asp:GridView>

Namespaces

C#

using System.Data;

VB.Net

Imports System.Data

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = GetDataTable();
        this.gvDates.DataSource = dt;
        this.gvDates.DataBind();
    }
}

private static DataTable GetDataTable()
{
    DataTable dt = new DataTable();
    dt.Columns.AddRange(new DataColumn[] { new DataColumn("Staff Name", typeof(string)), new DataColumn("Client Name", typeof(string)), new DataColumn("date1", typeof(DateTime)), new DataColumn("date2", typeof(DateTime)), new DataColumn("date3", typeof(DateTime)) });
    dt.Rows.Add("staff1", "client1", "2/11/2019", "2/4/2019", "1/1/0001");
    dt.Rows.Add("staff1", "client2", "2/25/2019", "2/18/2019", "1/1/0001");
    dt.Rows.Add("staff2", "client1", "1/1/0001", "1/1/0001", "1/1/0001");
    dt.Rows.Add("staff1", "client1", "2/11/2019", "2/4/2019", "1/1/0001");
    return dt;
}

protected void GetData(object sender, EventArgs e)
{
    DateTime date1 = Convert.ToDateTime(txtDate.Text);
    DataTable dt = GetDataTable();
    DataTable dt1 = new DataTable();
    DataRow[] results = dt.Select("Date1 = '" + date1.ToString("dd/MM/yyyy") + "' OR Date2 ='" + date1.ToString("dd/MM/yyyy") + "'OR Date3 ='" + date1.ToString("dd/MM/yyyy") + "'");
    if (results.Length != 0)
    {
        dt1 = results.CopyToDataTable();
        this.gvDates.DataSource = dt1;
        this.gvDates.DataBind();
    }
    else
    {
        this.gvDates.DataSource = dt;
        this.gvDates.DataBind();
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim dt As DataTable = GetDataTable()
        Me.gvDates.DataSource = dt
        Me.gvDates.DataBind()
    End If
End Sub

Private Shared Function GetDataTable() As DataTable
    Dim dt As DataTable = New DataTable()
    dt.Columns.AddRange(New DataColumn() {New DataColumn("Staff Name", GetType(String)), New DataColumn("Client Name", GetType(String)), New DataColumn("date1", GetType(DateTime)), New DataColumn("date2", GetType(DateTime)), New DataColumn("date3", GetType(DateTime))})
    dt.Rows.Add("staff1", "client1", "2/11/2019", "2/4/2019", "1/1/0001")
    dt.Rows.Add("staff1", "client2", "2/25/2019", "2/18/2019", "1/1/0001")
    dt.Rows.Add("staff2", "client1", "1/1/0001", "1/1/0001", "1/1/0001")
    dt.Rows.Add("staff1", "client1", "2/11/2019", "2/4/2019", "1/1/0001")
    Return dt
End Function

Protected Sub GetData(ByVal sender As Object, ByVal e As EventArgs)
    Dim date1 As DateTime = Convert.ToDateTime(txtDate.Text)
    Dim dt As DataTable = GetDataTable()
    Dim dt1 As DataTable = New DataTable()
    Dim results As DataRow() = dt.[Select]("Date1 = '" & date1.ToString("dd/MM/yyyy") & "' OR Date2 ='" + date1.ToString("dd/MM/yyyy") & "'OR Date3 ='" + date1.ToString("dd/MM/yyyy") & "'")
    If results.Length <> 0 Then
        dt1 = results.CopyToDataTable()
        Me.gvDates.DataSource = dt1
        Me.gvDates.DataBind()
    Else
        Me.gvDates.DataSource = dt
        Me.gvDates.DataBind()
    End If
End Sub

Screenshot