I have the following code to compare two dates with the following conditions
Scenario:
On load there are two text boxes (FromDate, ToDate) with Ajax calendar extenders.
On load From
Date shows today's
date.
when
date less than today was selected in both text boxes(FromDate, ToDate), it alerts user saying "You cannot select a day earlier than today!"
When ToDate's Selected
date < FromDate's Selected
Date, alerts user saying "To
Date must be Greater than From
date." and at the same
time it clears the selected
Date in ToDate Text box.
Codeblock:
ASP.NET , AJAX
<asp:TextBox ID="txtFrom" runat="server"
ReadOnly="true"></asp:TextBox>
<asp:ImageButton ID="imgBtnFrom" runat="server" ImageUrl="~/images/Cal20x20.png" Width="20" Height="20" ImageAlign="TextTop" />
<asp:CalendarExtender ID="txtFrom_CalendarExtender" PopupButtonID="imgBtnFrom"
runat="server" Enabled="True"
OnClientDateSelectionChanged="checkDate"
TargetControlID="txtFrom" Format="MMM d, yyyy">
</asp:CalendarExtender>
<asp:TextBox ID="txtTo" runat="server"
ReadOnly="true"></asp:TextBox>
<asp:ImageButton ID="imgBtnTo" runat="server" ImageUrl="~/images/Cal20x20.png" Width="20" Height="20" ImageAlign="TextTop" />
<asp:CalendarExtender ID="txtTo_CalendarExtender"
OnClientDateSelectionChanged="compareDateRange"
PopupButtonID="imgBtnTo"
runat="server"
Enabled="True" TargetControlID="txtTo"
Format="MMM d, yyyy">
</asp:CalendarExtender>
<asp:HiddenField ID="hdnFrom" runat="server" />
<asp:HiddenField ID="hdnTo" runat="server" />
C# Code
protected void Page_Load(object sender, EventArgs e)
{
txtFrom.Text = string.Format("{0: MMM d, yyyy}", DateTime.Today);
if (Page.IsPostBack)
{
if (!String.IsNullOrEmpty(hdnFrom.Value as string))
{
txtFrom.Text = hdnFrom.Value;
}
if (!String.IsNullOrEmpty(hdnTo.Value as string))
{
txtTo.Text = hdnTo.Value;
}
}
}
JavaScript Code
<script type="text/javascript">
function checkDate(sender, args) {
document.getElementById('<%=txtTo.ClientID %>').value = "";
if (sender._selectedDate < new Date()) {
alert("You cannot select a day earlier than today!");
sender._selectedDate = new Date();
// set the
date back to the current
date
sender._textbox.set_Value(sender._selectedDate.format(sender._format));
//assign the value to the hidden field.
document.getElementById('<%=hdnFrom.ClientID %>').value = sender._selectedDate.format(sender._format);
//reset the to
date to blank.
document.getElementById('<%=txtTo.ClientID %>').value = "";
} else {
document.getElementById('<%=hdnFrom.ClientID %>').value = sender._selectedDate.format(sender._format);
}
}
function compareDateRange(sender, args) {
var fromDateString = document.getElementById('<%=txtFrom.ClientID %>').value;
var fromDate = new Date(fromDateString);
if (sender._selectedDate < new Date()) {
alert("You cannot select a
Date earlier than today!");
sender._selectedDate = "";
sender._textbox.set_Value(sender._selectedDate)
}
if (sender._selectedDate <= fromDate) {
alert("To
Date must be Greater than From
date.");
sender._selectedDate = "";
sender._textbox.set_Value(sender._selectedDate)
} else {
document.getElementById('<%=hdnTo.ClientID %>').value = sender._selectedDate.format(sender._format);
}
}
</script>
Error Screen(Hmmm :X)
Now in ToDate, when you select
Date Earlier than today or
Date less than FromDate, ToDate Calendar shows NaN for Every
Date and ,0NaN for Year
