Creating a Custom DateTextbox User Control: Part I


I was working on an application for online store. I found that pretty often I would create a textbox and link it to a calendar extender to perform some date populating. So I decided to create a usercontrol that I could use each time I wanted to perform that task.

Here it is. Enjoy!!

First create a new usercontrol and name it "DateTextBox", check the box to place code in codebehind file. In design view drag and drop a textbox asp control on the page. Note: Use an asp textbox control not an html text field.

Give your textbox control an identifier. I called mine txtDateVal. Now still in design view use the smart tag of the textbox and click add extender.

Figure1.gif

Figure 1: adding extender.

Select the calendar extender. Give your extender an identifier and click ok. I used "cDateValue" for my identifier.

Figure2.gif

Figure 2: Choosing the calendar extender.

Next in the properties panel. If you don't see it go to "View" menu and select "Properties Window". Switch to code view and place your cursor over the code of the calender extender control... in the properties panel look for "TargetControlID" and type txtDateVal (or whatever name you assigned to your textbox control). You could also type it directly in the code of the calender extender; type TargetControlID="txtDateVal". What this does is set the text of the textbox control to the date selected in the calendar at runtime.

Figure3.gif

Figure 3: Assigning the TargetControlID property.

Now we're going to add validators to our control.

From the toolbox validators tab drag a RegularExpressionsValidator on to the page in code view assign it an identifier (ID) of "regDateValidator". Switch to design view and select the validator, set the "ValidationExpression" property to the following; ValidationExpression="\d{2}/\d{2}/\d{4}", and set the "Display" property to "None". Click add extender. Select the validation callout extender assign it an identifier and click ok. I gave mine an ID of "vceRegExpression".

From your toolbox validation tab drag a requiredfieldvalidator on to the page, assign it a name of "rqDateVal". Set it's "ControlToValidate" property to txtDateVal. Extend your requiredfieldvalidator with a validation callout extender

Your markup should now look something like the following ...

Figure4.gif

Now let's get into the fun stuff. Open your code page from the solution explorer. If you don't see the solution explorer, in your visual studio editor go to the "View" menu and click on "Solution Explorer".

Now that your code behind is opened we will add some Public Properties to our custom control. Why Public Properties? This makes our properties accessible to other controls and pages.

I think this would be a good time to point out that i'm using VB.NET for this example. If you're using C# or another .NET language your code will look different to mine, but i'll try to explain as clearly as possible so you can follow along.

Firstly, we want to reference a few namespaces so i'll import them in the top of my codebehind like this

Imports System
Imports System.Web
Imports System.Web.Security
Imports System.Web.UIImports System.Web.UI.WebControls

If you're using C# you'll use the keyword "using" instead of "Imports".

We are defining the basic properties that we want to make accessible to other controls.

these are ...

Text, TextMode, Width, Height, Enabled, ValidationGroup, ValidationText, ErrorMessage, IsRequired and AutoCompleteType

Let's begin

Note: don't worry about the namespace assignment. I used the namespace assignment of the solution for this control; you may use the namespace of yours (optional).

Imports System
Imports System.Web
Imports System.Web.Security
Imports System.Web.UI
Imports System.Web.UI.HtmlControls
Imports System.Web.UI.WebControls
Imports System.Globalization
Imports System.Text.RegularExpressions

Namespace Glaze.SmartCart.BLL.Common.UI.Web.Controls
    Partial Public Class DateTextBox
        Inherits UserControl

        Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
            If Not IsPostBack Then
                If Not Me.UsePopupButton Then
                    Me.PopupButtonID = "txtDateVal"
                End If
                If Not Me.IsRequired Then
                    Me.rqDateVal.Enabled = False
                End If
            End If
        End Sub

        Public Property Text() As String
            Get
                Return txtDateVal.Text
            End Get
            Set(ByVal value As String)
                txtDateVal.Text = value
            End Set
        End Property

        Public Property ErrorMessage() As String
            Get
                Return rqDateVal.ErrorMessage
            End Get
            Set(ByVal value As String)
                rqDateVal.ErrorMessage = value
            End Set
        End Property

        Public Property Enabled() As Boolean
            Get
                Return txtDateVal.Enabled
            End Get
            Set(ByVal value As Boolean)
                txtDateVal.Enabled = value
            End Set
        End Property

        Public Property Width() As Unit
            Get
                Return txtDateVal.Width
            End Get
            Set(ByVal value As Unit)
                txtDateVal.Width = value
            End Set
        End Property

        Public Property Height() As Unit
            Get
                Return txtDateVal.Height
            End Get
            Set(ByVal value As Unit)
                txtDateVal.Height = value
            End Set
        End Property

        Public Property TextMode() As TextBoxMode
            Get
                Return txtDateVal.TextMode
            End Get
            Set(ByVal value As TextBoxMode)
                txtDateVal.TextMode = value
            End Set
        End Property

 
       Public Property ValidationGroup() As String
            Get
                Return rqDateVal.ValidationGroup
            End Get
            Set(ByVal value As String)
                txtDateVal.ValidationGroup = value
                rqDateVal.ValidationGroup = value
            End Set
        End Property

        Public Property ValidationText() As String
            Get
                Return rqDateVal.Text().ToString
            End Get
            Set(ByVal value As String)
                rqDateVal.Text = value
            End Set
        End Property

        Public Shadows Property SkinID() As String
            Get
                Return txtDateVal.SkinID
            End Get
            Set(ByVal value As String)
                txtDateVal.SkinID = value
            End Set
        End Property

        Public Property AutoCompleteType() As AutoCompleteType
            Get
                Return txtDateVal.AutoCompleteType
            End Get
            Set(ByVal value As AutoCompleteType)
                txtDateVal.AutoCompleteType = value
            End Set
        End Property

        Property PopupButtonID() As String
            Get
                Return cDateVal.PopupButtonID
            End Get
            Set(ByVal value As String)
                cDateVal.PopupButtonID = value
            End Set
        End Property

        Public Property UsePopupButton() As Boolean
            Get
                Return CBool(Me.ViewState("PopupButton"))
            End Get
            Set(ByVal value As Boolean)
                Me.ViewState("PopupButton") = value
            End Set
        End Property

        Public Property IsRequired() As Boolean
            Get
                Return CBool(Me.ViewState("IsRequired"))
            End Get
            Set(ByVal value As Boolean)
                Me.ViewState("IsRequired") = value
            End Set
        End Property

        Public Property Extend() As Boolean
            Get
                Return CBool(Me.ViewState("Extend"))
            End Get
            Set(ByVal value As Boolean)
                Me.ViewState("Extend") = value
            End Set
        End Property
    End Class
End Namespace

Let's explain what we have so far.

On page load we want to set the popupbuttonid property of the calendar extender to the textbox's id if we're not using a calendar image button. The boolean property "UsePopupButton" is true if we're using an image button, and false if we're not. We also want to check whether or not the date textbox is a required field, if not then we disable the requiredfieldvalidator.

If Not Me.UsePopupButton Then
....
End If

The calendar control's "PopupButtonID" property gets set to the id of the textbox only if that statement evaluates to true. What is the "PopupButtonID" for? Well... at runtime when a user clicks on the control with the popupbuttonid identifier this invokes the calenderextender, and it lauches the calendar control. So if the Identifier is the textbox, when a user mouse clicks inside of the textbox this launches the calendar. Some designers use a calendar icon position to the right of the textbox... in this case when that icon is clicked the calendar launches. 

If Not Me.IsRequired Then
....
End If

TheRequiredFieldValidator control's "Enabled" property is set to false only if that statement evaluates to true.

All of the other properties should be pretty self explanatory.

That's it for part 1. Next I'll show you how to use your control in a page. Coming in part 2.

Happy programming!! :)


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