Running Total in DataList

Colonel Angus · October 23rd, 2004, 01:31 PM

Hello again-

One of the columns in my datalist contains an integer value. There are times in my list that I need to show the total for a number of rows.

For example,

1
2
2
--
5

2
1
3
--
6

and so on.

Here's my code:

Code:

Public CaseTotal As Integer = 0
.
.
Public Sub dlItemDataBound(ByVal sender As Object, ByVal e As DataListItemEventArgs)
        If e.Item.ItemType = ListItemType.Item Or e.Item.ItemType = ListItemType.AlternatingItem Then
            Dim CenterLabel, lblSep, Cases, Total As Label
            Select Case e.Item.ItemType
                Case ListItemType.Item
                    CenterLabel = CType(e.Item.FindControl("lblCenter"), Label)
                    lblSep = CType(e.Item.FindControl("lblSeparate"), Label)
                    Cases = CType(e.Item.FindControl("lblCases"), Label)
                    Total = CType(e.Item.FindControl("lblTotal"), Label)
                Case ListItemType.AlternatingItem
                    CenterLabel = CType(e.Item.FindControl("lblAltCenter"), Label)
                    lblSep = CType(e.Item.FindControl("lblAltSeparate"), Label)
                    Cases = CType(e.Item.FindControl("lblAltCases"), Label)
                    Total = CType(e.Item.FindControl("lblAltTotal"), Label)
            End Select

            CaseTotal += CInt(Cases.Text)
            Total.Text = "Total:&nbsp;&nbsp;&nbsp;" & FormatNumber(CaseTotal, 0, , , TriState.True)

            If curCenter = CenterLabel.Text Then
                CenterLabel.Visible = False
                lblSep.Visible = False
                Total.Visible = False
            Else
                'new Center
                CenterLabel.Visible = True
                lblSep.Visible = True
                Total.Visible = True
                CaseTotal = 0
            End If
            curCenter = CenterLabel.Text
        End If
    End Sub

The idea is to total up the value in lblCases to display when there is a new center.
The line

Code:

CaseTotal += CInt(Cases.Text)

gives an error, "InvalidCastException: Cast from string "" to type 'Integer' is not valid." That is, Cases.Text is empty.

What gives?

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In God we trust, everything else we test.

Colonel Angus · October 25th, 2004, 09:27 AM

FYI, I found the problem.

In the datalist, I had the lblCases defined like this:

Code:

<asp:Label id="lblCases" runat="server" CssClass="formlabel">
<%# Databinder.Eval(Container.DataItem,"NumCases")%>
</asp:Label>

When it should have been like this:

Code:

<asp:Label id="lblCases" runat="server" CssClass="formlabel" Text='<%# Databinder.Eval(Container.DataItem,"NumCases")%>'></asp:Label>

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In God we trust, everything else we test.