Count days out of gridview row databound in one cell

Question

Count days out of gridview row databound in one cell

Phillip Vong 121

First - Thanks for helping a newbie. Doing this in VB.net / asp.net.

Goal - During a GridView RowDataBound, I want to...

Check each row and see if Column 5 is Blank
If not blank
convert to date and see if that date is less than 365 of today
If less than 365, make that cell backcolor yellow

Col(5) data type in SQL is DATE
Col(5) DataFormatString in Gridview is {0:d}

My Code:

 Private Sub GridView1_RowDataBound(sender As Object, e As GridViewRowEventArgs) Handles GridView1.RowDataBound

        If Not e.Row.Cells(5).ToString = String.Empty Then

            Dim CoDateToDate As Date = Convert.ToDateTime(e.Row.Cells(5))
            Dim Ct As Int32 = DateDiff(DateInterval.Day, CoDateToDate.Day, Now.Day)

            If Ct < 365 Then
                e.Row.Cells(5).BackColor = Drawing.Color.Yellow
            End If
        End If


    End Sub

My Error Message
'Unable to cast object of type 'System.Web.UI.WebControls.DataControlFieldHeaderCell' to type 'System.IConvertible'.'

My Imports - don't know if I'm not importing the right things.
Imports System.Data, System.Data.SqlClient, System.Web.UI.WebControls

I didn't see a way to CONVERT to Date. I can only Convert to DateTime. Is this the problem with the SQL datatype is just DATE?

Please help and thanks!

0 comments

Answer accepted by question author

0 additional answers

Your answer

Answer 1

Albert Kallal 5,591

What you have looks ok - but when the data bound triggers, it ALSO will include the heading and the footing grid row - you ONLY want to process/run your code for a data row.

so, wrap your existing code in this:

    If e.Row.RowType = DataControlRowType.DataRow Then

    End If

Regards,
Albert D. Kallal (Access MVP 2003-2017)
Edmonton, Alberta Canada

Phillip Vong 121

I'm still getting the same error code after I wrap it all in what you said. Here's my updated code.

Private Sub GridView1_RowDataBound(sender As Object, e As GridViewRowEventArgs) Handles GridView1.RowDataBound

        If e.Row.RowType = DataControlRowType.DataRow Then
            If Not e.Row.Cells(5).ToString = String.Empty Then

                Dim CoDateToDate As Date = Convert.ToDateTime(e.Row.Cells(5))
                Dim Ct As Int32 = DateDiff(DateInterval.Day, CoDateToDate.Day, Now.Day)

                If Ct < 365 Then
                    e.Row.Cells(5).BackColor = Drawing.Color.Yellow
                End If
            End If
        End If

    End Sub

This is the line that's triggering the error.
Dim CoDateToDate As Date = Convert.ToDateTime(e.Row.Cells(5))

Details of the error below
$exception {"Unable to cast object of type 'System.Web.UI.WebControls.DataControlFieldCell' to type 'System.IConvertible'."} System.InvalidCastException

Albert Kallal 5,591

try:

       If e.Row.RowType = DataControlRowType.DataRow Then

             If e.Row.Cells(5).Text <> "" Then

                 Dim CoDateToDate As Date = e.Row.Cells(5).Text
                 Dim Ct As Int32 = DateDiff(DateInterval.Day, Date.Today,CoDateToDate)

                 If Ct < 365 Then
                     e.Row.Cells(5).BackColor = Drawing.Color.Yellow
                 End If
             End If
         End If

Phillip Vong 121 Reputation points

2021-07-06T00:51:12.283+00:00

I'm getting the below error trying to convert the text to date.

Dim CoDateToDate As Date = e.Row.Cells(5).Text

System.InvalidCastException: 'Conversion from string " " to type 'Date' is not valid.'
Albert Kallal 5,591 Reputation points

2021-07-06T02:57:53.443+00:00
This is why I spend time here!!

II never really checked/tested what a null data base value spits out. and I never really thought that html was shoved into a cell(). But it is!!!

So, you can us this:

If e.Row.Cells(5).Text <> " " Then

I will say, that I used grid view for years - never really had to test for a null/empty value, and when I did, it was usually in the SQL query.

Learn something new everyday!!!

Give above a try.. My bad, my wrong - those nulls for dates become the above string - test for that - the rest should start working.

And I did flip the dates on you - you (might) need to reverse them back. I always write my code to produce a positive value from todays date to one in the future. Since you looking for a past date? Then you want this for the date dif

Dim Ct As Int32 = DateDiff(DateInterval.Day, CoDateToDate, Date.Today)

So check that logic - but the code should at least run. and goolly gee - I just learned something new!!!

Regards,
Albert D. Kallal (Access MVP 2003-2017)
Edmonton, Alberta Canada
Yijing Sun-MSFT 7,106 Reputation points

2021-07-06T07:00:30.797+00:00

Hi @Phillip Vong ,
According to your problems,your e.Row.Cells(5).Text is blank.I suggest you could debug and check the value of e.Row.Cells(5).Text.
How do your write your data? Do you have bind database? If you bind database,it will tip "String was not recognized as a valid DateTime."
Could you post your data to us?
Best regards,
Yijing Sun
Phillip Vong 121 Reputation points

2021-07-06T16:43:04.827+00:00

BOOM- this fixed my problem.

If e.Row.Cells(5).Text <> " " Then

Share via

Count days out of gridview row databound in one cell

0 additional answers

Your answer