Loop

[OuTCasT]

I have 2 gridviews.
i need to loop through DG1 and DG2 and if there is a value present in DG2 i would like to remove it out of DG1.

Try
            For rowIndex = 0 To DataGridview1.RowCount - 2
 
                email = DataGridview1.Rows(rowIndex).Cells(0).Value.ToString
 
                For rowIndex1 = 0 To DataGridView2.RowCount - 2
 
                    email2 = DataGridView2.Rows(rowIndex1).Cells(0).Value.ToString
 
                    If email = email2 Then
                        DataGridview1.Rows.Remove(DataGridview1.Rows(rowIndex))
                    End If
 
                Next
 
            Next
 
 
 
        Catch ex As Exception
 
        End Try

This is the code that i am using but it doesnt seem to work properly.

I know that the rowIndex changes when something is deleted from DG1 but i cant seem to make the code work for me.

[Plater]

If DG1 is your outer loop, everytime you delete an entry from it, you must subtract one from the index for DG1.
Would it not work better to make DG2 your outer loop?(Unless DG2 is much bigger then DG1)

[OuTCasT]

DG1 is the large one.
I see that it starts on rowIndex 1 usually after u have deleted a row, depending where the row was in the index it wld most probably change.

Now when ive deleted the first duplicated row i try set the rowindex to start at 0 again but then the loop becomes infinate.

[Plater]

You don't want to set it to 0, just subtract one.
So thenyou would have this:

If email = email2 Then 
   DataGridview1.Rows.Remove(DataGridview1.Rows(rowIndex)) 
   rowIndex=rowIndex-1
End If 
 

[OuTCasT]

Thanks that seems to have done the trick although it does come up with an error. But i have put it in a try catch so that it skips the error

Try
            For rowIndex = 0 To DataGridview1.RowCount - 2
 
                email = DataGridview1.Rows(rowIndex).Cells(0).Value.ToString
 
                For rowIndex1 = 0 To DataGridView2.RowCount - 2
 
                    email2 = DataGridView2.Rows(rowIndex1).Cells(0).Value.ToString
 
                    If email = email2 Then
                        DataGridview1.Rows.Remove(DataGridview1.Rows(rowIndex))
                        rowIndex = rowIndex - 1
                    End If
 
                Next
 
            Next
 
 
 
        Catch ex As Exception
 
        End Try

[Plater]

Hmm what is the exception that it throws? Is it IndexOutOfRange ? I am not sure how VB does its looping, but if you remove the first object (when the index=0) then the removal would make the index be -1, which might cause problems?

[OuTCasT]

Its either object not set to a reference or index out of range.
What i did was i fill the DG1 from the excel sheet. Then build a query string containing the email from DG1 and query the database for those email addresses. Then fill DG2 with those email addresses. I did a rowcount on the DG2 and used the loop in question above and put it in a loop

dim i as integer
for i = 0 to label1.text
     RemoveLists
next

so it would definately loop through the amounts found in DG2 and remove them from DG1.