Calculate days difference between two Dates excluding holidays using C# and VB.Net in ASP.Net

Hi kankon,

Please refer below sample.

HTML

<asp:TextBox runat="server" ID="txtBox1" />
<asp:TextBox runat="server" ID="txtbox2" />
<br /><asp:Button Text="Submit" runat="server" OnClick="Submit_OnClick" />
<br /><asp:Label Text="" runat="server" ID="lblLabel1" />

Namespace

C#

using System;
using System.Collections.Generic;

VB.Net

Imports System
Imports System.Collections.Generic

Code

C#

protected void Submit_OnClick(object sender, EventArgs e)
{
    DateTime d1 = Convert.ToDateTime(txtBox1.Text);
    DateTime d2 = Convert.ToDateTime(txtbox2.Text);
    var totalDays = (d2 - d1).Days;
    int wd = 0;
    for (int x = 0; x <= totalDays; x++)
    {
        DateTime currendDate = d1.AddDays(x);
        if (currendDate.DayOfWeek != DayOfWeek.Friday)
        {
            if (!Holiday().Contains(d1.AddDays(x)))
            {
                wd += 1;
            }
        }
    }
    lblLabel1.Text = wd.ToString();
}

private List<DateTime> Holiday()
{
    List<DateTime> dates = new List<DateTime>();
    dates.Add(new DateTime(2019, 01, 01));
    dates.Add(new DateTime(2019, 02, 25));
    dates.Add(new DateTime(2019, 02, 26));
    dates.Add(new DateTime(2019, 04, 04));
    dates.Add(new DateTime(2019, 08, 31));
    dates.Add(new DateTime(2019, 09, 11));

    return dates;
}

VB.Net

Protected Sub Submit_OnClick(ByVal sender As Object, ByVal e As EventArgs)
    Dim d1 As DateTime = Convert.ToDateTime(txtBox1.Text)
    Dim d2 As DateTime = Convert.ToDateTime(txtbox2.Text)
    Dim totalDays = (d2 - d1).Days
    Dim wd As Integer = 0
    For x As Integer = 0 To totalDays
        Dim currendDate As DateTime = d1.AddDays(x)
        If currendDate.DayOfWeek <> DayOfWeek.Friday Then
            If Not Holiday().Contains(d1.AddDays(x)) Then
                wd += 1
            End If
        End If
    Next
    lblLabel1.Text = wd.ToString()
End Sub

Private Function Holiday() As List(Of DateTime)
    Dim dates As List(Of DateTime) = New List(Of DateTime)()
    dates.Add(New DateTime(2019, 1, 1))
    dates.Add(New DateTime(2019, 2, 25))
    dates.Add(New DateTime(2019, 2, 26))
    dates.Add(New DateTime(2019, 4, 4))
    dates.Add(New DateTime(2019, 8, 31))
    dates.Add(New DateTime(2019, 9, 11))
    Return dates
End Function