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Item bata bound event causing an error

I am trying to create a databound event for my hyperlink when it is blank from the database.
but when I impliment it it causes errors on the datagrid, but when I put same code in db it works, it also works when I comment out the ItemDatabound event, but what happens is some items are not links on the datagrid but just blank.

Private Sub myDataGrid_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DataGridItemEventArgs) Handles myDataGrid.ItemDataBound
        Dim Fixpage As String = e.Item.Cells(4).Text
        Dim hl As HyperLink = e.Item.Cells(4).FindControl("hlFix")

        If Fixpage = "&nbsp;" Or Fixpage = "" Then
            hl.NavigateUrl = "http://sharepoint/JFHQ/JSTAFF/J1/J1ARMY/Mob/Mob%20Tracker%20Fix%20Pages/Fix%20Page%20Library.aspx"
        End If
    End Sub


<asp:TemplateColumn HeaderText="Fix Page">
											<ItemTemplate>
												<asp:Hyperlink id="hlFix" runat="server" Text="Fix Page" NavigateUrl='<%# DataBinder.Eval (Container.DataItem,"strFilterPage") %>' Target="_blank"></asp:Hyperlink>  
											</ItemTemplate>
										</asp:TemplateColumn>

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guru_sami

Whats the error ?

May be because NavigateUrl='<%# DataBinder.Eval (Container.DataItem,"strFilterPage") %>' is throwing error due to null value in database.

Can you try:
.aspx
NavigateUrl='<%# GetUrl(Eval("strFilterPage"))%>'

.aspx.vb

Public Function GetUrl(ByVal strFilterPage As Object) As String
Dim url As String = DirectCast(strFilterPage, String)
If strFilterPage Is Nothing or strFilterPage = String.EmptyThen
url = "http://sharepoint/JFHQ/JSTAFF/J1/J1ARMY/Mob/Mob%20Tracker%20Fix%20Pages/Fix%20Page%20Library.aspx"
End If
Return url
End Function

Note: There could be some other way....

kdeutsch

ASKER

Sorry this is the error,

When I comment out these lines it works good,
If Fixpage = " " Or Fixpage = "" Then
hl.NavigateUrl = "http://sharepoint/JFHQ/JSTAFF/J1/J1ARMY/Mob/Mob%20Tracker%20Fix%20Pages/Fix%20Page%20Library.aspx"
End If

Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.]
MobTrackerDotNet.StandardReports.myDataGrid_ItemDataBound(Object sender, DataGridItemEventArgs e) in R:\Inetpub\wwwroot\MobTrackerDotNet\Reports\StandardReports.aspx.vb:568
System.Web.UI.WebControls.DataGrid.OnItemDataBound(DataGridItemEventArgs e) +110
System.Web.UI.WebControls.DataGrid.CreateItem(Int32 itemIndex, Int32 dataSourceIndex, ListItemType itemType, Boolean dataBind, Object dataItem, DataGridColumn[] columns, TableRowCollection rows, PagedDataSource pagedDataSource) +181
System.Web.UI.WebControls.DataGrid.CreateControlHierarchy(Boolean useDataSource) +1485
System.Web.UI.WebControls.BaseDataList.OnDataBinding(EventArgs e) +49
System.Web.UI.WebControls.BaseDataList.DataBind() +23
MobTrackerDotNet.StandardReports.FillDataGrid() in R:\Inetpub\wwwroot\MobTrackerDotNet\Reports\StandardReports.aspx.vb:165
MobTrackerDotNet.StandardReports.ddlDeployment_SelectedIndexChanged(Object sender, EventArgs e) in R:\Inetpub\wwwroot\MobTrackerDotNet\Reports\StandardReports.aspx.vb:93
System.Web.UI.WebControls.ListControl.OnSelectedIndexChanged(EventArgs e) +108
System.Web.UI.WebControls.DropDownList.System.Web.UI.IPostBackDataHandler.RaisePostDataChangedEvent() +26
System.Web.UI.Page.RaiseChangedEvents() +115
System.Web.UI.Page.ProcessRequestMain() +1099

guru_sami

ok add a check before that...
if hl IsNot nothing then

SOLUTION

codingbeaver

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kdeutsch

ASKER

Hi,
HL isNot Nothing gives me Blue errors, still working in 1.1.
Tried this but gives me errors as well
If hl = "" Then
If Fixpage = " " Or Fixpage = "" Then
hl.NavigateUrl = "http://sharepoint/JFHQ/JSTAFF/J1/J1ARMY/Mob/Mob%20Tracker%20Fix%20Pages/Fix%20Page%20Library.aspx"
End If
End If

kdeutsch

ASKER

Oh,
the erro for that is Operator is not defined for types system.web.uic.webcontrols.hyperlink & string

kdeutsch

ASKER

All,
the realization just hit me that checking agianst the text in the cell will never work because it will never be blank, it will always have Fix page in it, but what is blank is the data behind the link. How do I access this data????

codingbeaver

In your ItemDataBound event handler, you will first need to check if it is a Header row or a Item row, because the event handler loops through all rows in the DataGrid, starting from the Header row.

kdeutsch

ASKER

Ok, I am really getting confused witht this now, it does not give the error above when I put in the alternating item it seemed to disapppear, but some elements in cell 4 of the datagrid do not appear with a blue link becuase they have no database element attached to them. I put in the check for header footer but I don't see how thats solving the problem of checking for data behind the link.

If (e.Item.ItemType = ListItemType.Item Or e.Item.ItemType = ListItemType.AlternatingItem) Then
Dim Fixpage As String = e.Item.Cells(4).Text
Dim hl As HyperLink = e.Item.Cells(4).FindControl("hlFix")
If (e.Item.ItemType = ListItemType.Header Or e.Item.ItemType = ListItemType.Footer) Then
If e.Item.Cells(4).Text = " " Then
hl.NavigateUrl = "http://sharepoint/JFHQ/JSTAFF/J1/J1ARMY/Mob/Mob%20Tracker%20Fix%20Pages/Fix%20Page%20Library.aspx"
End If
End If
End If

codingbeaver

Are you trying to change the url only for header and footer? If not, then remove the checking for Header and Footer.

If (e.Item.ItemType = ListItemType.Item Or e.Item.ItemType = ListItemType.AlternatingItem) Then
	Dim Fixpage As String = e.Item.Cells(4).Text
	Dim hl As HyperLink = e.Item.Cells(4).FindControl("hlFix")
	If (Not hl Is Nothing) Then
		If e.Item.Cells(4).Text = "&nbsp;" Then
			hl.NavigateUrl = "http://sharepoint/JFHQ/JSTAFF/J1/J1ARMY/Mob/Mob%20Tracker%20Fix%20Pages/Fix%20Page%20Library.aspx"
		End If
	End If
End If

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ASKER CERTIFIED SOLUTION

guru_sami

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kdeutsch

ASKER

Got it to work by going directly to the datarow. Thanks for everyones help. I had to spread points on this because I would be remiss if I did not acknowledge help from others.