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DataBinding to CheckBoxList Control?
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This message was discovered on ASPFriends.com 'aspngcontrolsvb' list.


Mike Amundsen
I can't seem to find a way to complete databinding for a CheckBoxList
control.

With RadioButtonList controls I can use the DataTextField and DataValueField
properties to bind both display and datastorage values to the controls.
However, this is ignored by the CheckBoxList control and I see nothing in
the docs that say much about this.

Any help would be appreciated. Below is a simple page that I would expect to
display *all* values checked ON when the page first loads. However they are
alway all checked off instead.

TIA

MCA
Mike Amundsen
host your .NET Webs @ www.EraServer.NET

CODE FOLLOWS:
***************************************
<%@ Page Description="CheckBoxListDB.aspx" %>
<%@ import namespace="System.Data" %>

<script Language="VB" runat="server">

' display list the very first time only
sub Page_Load(Source As object, e As EventArgs)

if IsPostBack=false then
with cbListDB
.DataSource = CreateDataSource()
.DataTextField="ItemName"
.DataValueField="ItemSelected"
.DataBind()
end with
end if

end sub

' build selection list for display
sub Check_Clicked(sender As Object, e As EventArgs)

Dim i As Integer

Message.Text = "You selected:<ul>"

For i=0 To cbListDB.Items.Count - 1
If cbListDB.Items(i).Selected Then
Message.Text &= "<li>" & cbListDB.Items(i).Text & "</li>"
End If
Next

Message.Text &= "</ul>"

end sub

' create some data for this example
function CreateDataSource() as DataView

dim dt as DataTable = new DataTable()
dim dr as DataRow
dim i as integer

with dt.Columns
.Add(new DataColumn("ItemName",GetType(String)))
.Add(new DataColumn("ItemSelected",GetType(boolean)))
end with

for i=0 to 4
dr = dt.NewRow()
dr(0) = "Widget " & chr(i+65)
dr(1) = true

dt.rows.Add(dr)
next

dim dv as DataView = new DataView(dt)
return dv

end function

</script>

<body>

<h2>Data Bound Check Box List Demo</h2>
<hr />

<form runat="server">

<asp:CheckBoxList id="cbListDB"
RepeatColumns="2"
TextAlign="right"
AutoPostBack="True"
OnSelectedIndexChanged="Check_Clicked"
runat="server">

</asp:CheckBoxList>

<p>
<asp:label id="Message" runat="server"/>
</p>

</form>
</body>
</html>
Reply to this message...
 
    
Doug Seven

Mike,

Here is a working sample for you. It seemed to work as expected. Are you
getting an error message?

<%@ Page Language="VB" %>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.SqlClient" %>

<script runat="server">
Sub Page_Load(Sender As Object, E As EventArgs)
If Not Page.IsPostBack Then
Dim myDataSet As New DataSet
Dim myDataAdapter As SqlDataAdapter

myDataAdapter = New SqlDataAdapter("SELECT TOP 5 * FROM Customers",
"server=localhost;database=Northwind;uid=sa;pwd=;")
myDataAdapter.Fill(myDataSet, "Customers")

With myCheckboxList
    .DataSource = myDataSet.Tables("Customers")
    .DataValueField="CustomerID"
    .DataTextField="CompanyName"
End With
Page.DataBind()
Else
Response.Write("You Chose: " + myCheckboxList.SelectedItem.Value)
End If
End Sub
</script>
<html>
<body>
<form runat="server">
<p>
<b>Binding to a CheckboxList</b><br>
<asp:CheckboxList id="myCheckboxList" runat="server" />
</p>
<asp:Button runat="server" Text="Submit" />
</form>
</body>
</html>
______________________________________________
doug.seven | sr. junkie | www.dotnetjunkies.com

[ putting the dot in .net ]

programming data-driven web applications with asp.net
by doug.seven and donny.mack
http://www.amazon.com/exec/obidos/ASIN/0672321068/dotnetjunkies-20/

"Honestly, this really isn't a brains kind of operation"
- Benicio del Toro, The Way of the Gun

-----Original Message-----
From: Mike Amundsen [mailto:Click here to reveal e-mail address]
Sent: Thursday, August 02, 2001 11:59 AM
To: aspngcontrolsvb
Subject: [aspngcontrolsvb] DataBinding to CheckBoxList Control???

I can't seem to find a way to complete databinding for a CheckBoxList
control.

With RadioButtonList controls I can use the DataTextField and DataValueField
properties to bind both display and datastorage values to the controls.
However, this is ignored by the CheckBoxList control and I see nothing in
the docs that say much about this.

Any help would be appreciated. Below is a simple page that I would expect to
display *all* values checked ON when the page first loads. However they are
alway all checked off instead.

TIA

MCA
Mike Amundsen
host your .NET Webs @ www.EraServer.NET

CODE FOLLOWS:
***************************************
<%@ Page Description="CheckBoxListDB.aspx" %>
<%@ import namespace="System.Data" %>

<script Language="VB" runat="server">

' display list the very first time only
sub Page_Load(Source As object, e As EventArgs)

if IsPostBack=false then
with cbListDB
.DataSource = CreateDataSource()
.DataTextField="ItemName"
.DataValueField="ItemSelected"
.DataBind()
end with
end if

end sub

' build selection list for display
sub Check_Clicked(sender As Object, e As EventArgs)

Dim i As Integer

Message.Text = "You selected:<ul>"

For i=0 To cbListDB.Items.Count - 1
If cbListDB.Items(i).Selected Then
Message.Text &= "<li>" & cbListDB.Items(i).Text & "</li>"
End If
Next

Message.Text &= "</ul>"

end sub

' create some data for this example
function CreateDataSource() as DataView

dim dt as DataTable = new DataTable()
dim dr as DataRow
dim i as integer

with dt.Columns
.Add(new DataColumn("ItemName",GetType(String)))
.Add(new DataColumn("ItemSelected",GetType(boolean)))
end with

for i=0 to 4
dr = dt.NewRow()
dr(0) = "Widget " & chr(i+65)
dr(1) = true

dt.rows.Add(dr)
next

dim dv as DataView = new DataView(dt)
return dv

end function

</script>

<body>

<h2>Data Bound Check Box List Demo</h2>
<hr />

<form runat="server">

<asp:CheckBoxList id="cbListDB"
RepeatColumns="2"
TextAlign="right"
AutoPostBack="True"
OnSelectedIndexChanged="Check_Clicked"
runat="server">

</asp:CheckBoxList>

<p>
<asp:label id="Message" runat="server"/>
</p>

</form>
</body>
</html>

| [aspngcontrolsvb] member Click here to reveal e-mail address = YOUR ID
| http://www.asplists.com/asplists/aspngcontrolsvb.asp = JOIN/QUIT
| http://www.asplists.com/search = SEARCH Archives
Reply to this message...
 
    
Mike Amundsen
DS:

Thanks for the post. Your example works, but not as I had hoped.

I am trying to databind to the *Checked* property of the control. In
otherwords, for all items that have a column set to TRUE, I was expecting to
see the checkbox turned ON.

Basically, I am expecting to be able to Bind to the Checked Property of the
collection, but I don't see this anywhere.

Seems a disappointment that I would need to 'bixel' through the list to set
the proper Checked=true, Checked=false properties for all the controls in
the databound list.

Maybe a function....

MCA

"Doug Seven" <Click here to reveal e-mail address> wrote in message
news:451392@aspngcontrolsvb...
[Original message clipped]
Reply to this message...
 
    
Doug Seven

Mike,

Here's a revised sample. Not sure if this is what you are looking for (I
don't think it is), but it is a viable workaround. I added an event handler
for the CheckBox.OnLoad event and set the Selected property there.

<%@ Page Language="VB" %>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.SqlClient" %>

<script runat="server">
Sub Page_Load(Sender As Object, E As EventArgs)
If Not Page.IsPostBack Then
Dim myDataSet As New DataSet
Dim myDataAdapter As SqlDataAdapter

myDataAdapter = New SqlDataAdapter("SELECT TOP 5 * FROM Customers",
"server=localhost;database=Northwind;uid=sa;pwd=;")
myDataAdapter.Fill(myDataSet, "Customers")

With myCheckboxList
    .DataSource = myDataSet.Tables("Customers")
    .DataValueField="CustomerID"
    .DataTextField="CompanyName"
End With
Page.DataBind()
Else
Response.Write("You Chose: " + myCheckboxList.SelectedItem.Value)
End If
End Sub

Sub Check_OnLoad(Sender As Object, E As EventArgs)
    Dim i As Integer
    For i = 0 to myCheckboxList.Items.Count-1
        If myCheckboxList.Items(i).Value.StartsWith("A") Then
            myCheckboxList.Items(i).Selected = True
        End If
    Next
End Sub
</script>
<html>
<body>
<form runat="server">
<p>
<b>Binding to a CheckboxList</b><br>
<asp:CheckboxList id="myCheckboxList" runat="server"
OnLoad="Check_OnLoad"/>
</p>
<asp:Button runat="server" Text="Submit" />
</form>
</body>
</html>

______________________________________________
doug.seven | sr. junkie | www.dotnetjunkies.com

[ putting the dot in .net ]

programming data-driven web applications with asp.net
by doug.seven and donny.mack
http://www.amazon.com/exec/obidos/ASIN/0672321068/dotnetjunkies-20/

"Honestly, this really isn't a brains kind of operation"
- Benicio del Toro, The Way of the Gun

-----Original Message-----
From: Mike Amundsen [mailto:Click here to reveal e-mail address]
Sent: Thursday, August 02, 2001 12:42 PM
To: aspngcontrolsvb
Subject: [aspngcontrolsvb] Re: DataBinding to CheckBoxList Control???

DS:

Thanks for the post. Your example works, but not as I had hoped.

I am trying to databind to the *Checked* property of the control. In
otherwords, for all items that have a column set to TRUE, I was expecting to
see the checkbox turned ON.

Basically, I am expecting to be able to Bind to the Checked Property of the
collection, but I don't see this anywhere.

Seems a disappointment that I would need to 'bixel' through the list to set
the proper Checked=true, Checked=false properties for all the controls in
the databound list.

Maybe a function....

MCA

"Doug Seven" <Click here to reveal e-mail address> wrote in message
news:451392@aspngcontrolsvb...
[Original message clipped]

| [aspngcontrolsvb] member Click here to reveal e-mail address = YOUR ID
| http://www.asplists.com/asplists/aspngcontrolsvb.asp = JOIN/QUIT
| http://www.asplists.com/search = SEARCH Archives
Reply to this message...
 
    
Mike Amundsen
DS:

yep, this is a decent workaround that accomplishes what I was hoping for.

Looks like another solution would be to create a derived class
"myCheckBoxList" that has a new bindable property, but I haven't tried that
yet.

Thanks for your help!

MCA
Mike Amundsen
host your .NET Webs at www.EraServer.NET

-----Original Message-----
From: Doug Seven [mailto:Click here to reveal e-mail address]
Sent: Thursday, August 02, 2001 2:58 PM
To: aspngcontrolsvb
Subject: [aspngcontrolsvb] Re: DataBinding to CheckBoxList Control???

Mike,

Here's a revised sample. Not sure if this is what you are looking for (I
don't think it is), but it is a viable workaround. I added an event handler
for the CheckBox.OnLoad event and set the Selected property there.

<%@ Page Language="VB" %>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.SqlClient" %>

<script runat="server">
Sub Page_Load(Sender As Object, E As EventArgs)
If Not Page.IsPostBack Then
Dim myDataSet As New DataSet
Dim myDataAdapter As SqlDataAdapter

myDataAdapter = New SqlDataAdapter("SELECT TOP 5 * FROM Customers",
"server=localhost;database=Northwind;uid=sa;pwd=;")
myDataAdapter.Fill(myDataSet, "Customers")

With myCheckboxList
    .DataSource = myDataSet.Tables("Customers")
    .DataValueField="CustomerID"
    .DataTextField="CompanyName"
End With
Page.DataBind()
Else
Response.Write("You Chose: " + myCheckboxList.SelectedItem.Value)
End If
End Sub

Sub Check_OnLoad(Sender As Object, E As EventArgs)
    Dim i As Integer
    For i = 0 to myCheckboxList.Items.Count-1
        If myCheckboxList.Items(i).Value.StartsWith("A") Then
            myCheckboxList.Items(i).Selected = True
        End If
    Next
End Sub
</script>
<html>
<body>
<form runat="server">
<p>
<b>Binding to a CheckboxList</b><br>
<asp:CheckboxList id="myCheckboxList" runat="server"
OnLoad="Check_OnLoad"/>
</p>
<asp:Button runat="server" Text="Submit" />
</form>
</body>
</html>

______________________________________________
doug.seven | sr. junkie | www.dotnetjunkies.com

[ putting the dot in .net ]

programming data-driven web applications with asp.net
by doug.seven and donny.mack
http://www.amazon.com/exec/obidos/ASIN/0672321068/dotnetjunkies-20/

"Honestly, this really isn't a brains kind of operation"
- Benicio del Toro, The Way of the Gun

-----Original Message-----
From: Mike Amundsen [mailto:Click here to reveal e-mail address]
Sent: Thursday, August 02, 2001 12:42 PM
To: aspngcontrolsvb
Subject: [aspngcontrolsvb] Re: DataBinding to CheckBoxList Control???

DS:

Thanks for the post. Your example works, but not as I had hoped.

I am trying to databind to the *Checked* property of the control. In
otherwords, for all items that have a column set to TRUE, I was expecting to
see the checkbox turned ON.

Basically, I am expecting to be able to Bind to the Checked Property of the
collection, but I don't see this anywhere.

Seems a disappointment that I would need to 'bixel' through the list to set
the proper Checked=true, Checked=false properties for all the controls in
the databound list.

Maybe a function....

MCA

"Doug Seven" <Click here to reveal e-mail address> wrote in message
news:451392@aspngcontrolsvb...
[Original message clipped]

| [aspngcontrolsvb] member Click here to reveal e-mail address = YOUR ID
| http://www.asplists.com/asplists/aspngcontrolsvb.asp = JOIN/QUIT
| http://www.asplists.com/search = SEARCH Archives

| [aspngcontrolsvb] member Click here to reveal e-mail address = YOUR ID
| http://www.asplists.com/asplists/aspngcontrolsvb.asp = JOIN/QUIT
| http://www.asplists.com/search = SEARCH Archives
Reply to this message...
 
 
System.Data.DataColumn
System.Data.DataRow
System.Data.DataSet
System.Data.DataTable
System.Data.DataView
System.Data.SqlClient.SqlDataAdapter
System.EventArgs
System.Messaging.Message
System.Web.UI.DataBinding
System.Web.UI.Page
System.Web.UI.WebControls.CheckBoxList
System.Web.UI.WebControls.RadioButtonList
System.Web.UI.WebControls.TextAlign
System.Windows.Forms.CheckBox




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