Hi nauna,
Please refer below sample.
HTML
<asp:Label ID="lblResult" runat="server" />
Code
C#
protected void Page_Load(object sender, EventArgs e)
{
double unixDate = 1550224760;
System.DateTime dtDateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc);
dtDateTime = dtDateTime.AddSeconds(unixDate).ToLocalTime();
lblResult.Text = "Converted Date is : <b>" + dtDateTime.ToString("dd/MM/yyyy") + "</b>";
}
VB.Net
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
Dim unixDate As Double = 1550224760
Dim dtDateTime As System.DateTime = New DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc)
dtDateTime = dtDateTime.AddSeconds(unixDate).ToLocalTime()
lblResult.Text = "Converted Date is : <b>" & dtDateTime.ToString("dd/MM/yyyy") & "</b>"
End Sub
Output
Converted Date is : 15/02/2019