Portal Error - A DropDownList cannot have multiple items selected.

[Tom Bray]

Ok I am baffled I can not figure out this problem. I am getting the
following error:

Portal Error - A DropDownList cannot have multiple items selected.

Error information
Name Value
Message A DropDownList cannot have multiple items selected.
Source System.Web
TargetSite Void RenderContents( System.Web.UI.H tmlTextWriter)
StackTrace at
System.Web.UI.W ebControls.Drop DownList.Render Contents(HtmlTe xtWriter writer)
at System.Web.UI.W ebControls.WebC ontrol.Render(H tmlTextWriter writer) at
System.Web.UI.C ontrol.RenderCo ntrol(HtmlTextW riter writer) at
System.Web.UI.C ontrol.RenderCh ildren(HtmlText Writer writer) at
System.Web.UI.C ontrol.Render(H tmlTextWriter writer) at
System.Web.UI.C ontrol.RenderCo ntrol(HtmlTextW riter writer) at
System.Web.UI.C ontrol.RenderCh ildren(HtmlText Writer writer) at
System.Web.UI.H tmlControls.Htm lContainerContr ol.Render(HtmlT extWriter
writer) at System.Web.UI.C ontrol.RenderCo ntrol(HtmlTextW riter writer) at
System.Web.UI.C ontrol.RenderCh ildren(HtmlText Writer writer) at
System.Web.UI.H tmlControls.Htm lForm.RenderChi ldren(HtmlTextW riter writer) at
System.Web.UI.H tmlControls.Htm lForm.Render(Ht mlTextWriter output) at
System.Web.UI.C ontrol.RenderCo ntrol(HtmlTextW riter writer) at
System.Web.UI.C ontrol.RenderCh ildren(HtmlText Writer writer) at
System.Web.UI.C ontrol.Render(H tmlTextWriter writer) at
System.Web.UI.C ontrol.RenderCo ntrol(HtmlTextW riter writer) at
System.Web.UI.P age.ProcessRequ estMain()
Also, I do you use the clearselection( ) method before loading any drop downs
so please do not offer that as a solution. Also, how come I don't get the
line number of the control that is having the problem? I am running IIS 5.0
and this using 1.1 framework.

Please help this won't go away ;).

--Tom

[JeffSchumacher]

I've had the same problem in different variations. Sometimes it's bee
due to databinding to a field with a NULL value. Other times ther
seems to be a problem with the RequiredFieldVa lidator and the dropdow
list control. I have one page in particular that gives this sam
exception after I use the Validate method on th
RequiredFieldVa lidator. Strangely enough, it seems to reset all of th
dropdown list controls on my page to have a selectedindex of 0, plus th
selectedindex that was previously set. I've been able to trap this b
adding an exception handler in the Render page override

--
JeffSchumache
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[JeffSchumacher]

Turns out that what was causing my problem did have something to do wit
the RequiredFieldVa lidator control a ListItem object I used to add
"Please Select" option to each of four dropdowns. The code looke
something like this:

Dim tempItem As New System.Web.UI.W ebControls.List Item
tempItem.Text = "Please select..."
tempItem.Value = ""
tempItem.Select ed = False
Me.ddlTest1.Ite ms.Insert(0, tempItem)
Me.ddlTest2.Ite ms.Insert(0, tempItem)
Me.ddlTest3.Ite ms.Insert(0, tempItem)
Me.ddlTest4.Ite ms.Insert(0, tempItem)

To correct the problem, I used separate ListItem variables for eac
control:

Dim tempItem As New System.Web.UI.W ebControls.List Item
tempItem.Text = "Please select..."
tempItem.Value = ""
tempItem.Select ed = False
Me.ddlTest1.Ite ms.Insert(0, tempItem)

Dim tempItem2 As New System.Web.UI.W ebControls.List Item
tempItem2.Text = "Please select..."
tempItem2.Value = ""
tempItem2.Selec ted = False
Me.ddlTest2.Ite ms.Insert(0, tempItem2)

Dim tempItem3 As New System.Web.UI.W ebControls.List Item
tempItem3.Text = "Please select..."
tempItem3.Value = ""
tempItem3.Selec ted = False
Me.ddlTest3.Ite ms.Insert(0, tempItem3)

Dim tempItem4 As New System.Web.UI.W ebControls.List Item
tempItem4.Text = "Please select..."
tempItem4.Value = ""
tempItem4.Selec ted = False
Me.ddlTest4.Ite ms.Insert(0, tempItem4)

My guess is the the Validate function somehow uses a reference to th
original tempItem variable I had defined, and there were 4 control
referencing that variable. Go figure

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JeffSchumache
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