how to remove cell value in the cell offset if a new value with the same data repeated after that? - excel

Question

I want to make a loop in range to zero the offset cell if the cell data is repeated next as below:
Column A Column B
T10 5
T20 10
T10 15
You see I have T10 Repeated maybe after one or many rows, What I want is to use only the last value for T10 (Which is 15 in this example) and make 5 = 0
I use this code in vb.net
Private Sub AdjustTotalStoreWeightPerDiamater()
wb = Workbook Path ...
ws = Worksheet Name ...
lr = last row
Rng = Column Range
Cel = Column Range
i = integer
With ws
lr = .Range("A" & .Rows.Count).End(Excel.XlDirection.xlUp).Row
Rng = ws.Range("A2", "A" & lr)
End With
For i = 2 To lr
For Each Cel In Rng.Cells
If Cel.Value = Cel.Offset(-1, 0).Value Then
Cel.Offset(0, 3).Value = 0
End If
Next
Next
End Sub
But the code does not sense that T10 = T10 to make the change.
Appreciate your support.

Answer 1

I used OleDb to get the data from Excel as a DataTable. Note that I used Extended Properties=""Excel 12.0;HDR=YES;""" at the end of the connection string so we would get the column headers.
Private Function GetExcelData() As System.Data.DataTable
Dim dt As New System.Data.DataTable
Dim ConStr = $"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\xxxx\Documents\Code\TestCode3\TestCode3\bin\Debug\TestCode1.xlsx;Extended Properties=""Excel 12.0;HDR=YES;"""
Dim SheetName = "Sheet1$"
Using cn = New OleDb.OleDbConnection(ConStr)
Using cmd As New OleDbCommand($"Select * From [{SheetName}];", cn)
cn.Open()
Using dr As OleDbDataReader = cmd.ExecuteReader
dt.Load(dr)
End Using
End Using
End Using
Return dt
End Function
To save the data back to the same excel sheet I used office automation.
Private Sub SaveDataTableToExcel(dt As System.Data.DataTable, RowToStartAt As Integer)
Dim FileToOpen = "C:\Users\xxxx\Documents\Code\TestCode3\TestCode3\bin\Debug\TestCode1.xlsx"
Dim xl As New Excel.Application
Dim wb = DirectCast(xl.Workbooks.Open(FileToOpen), Workbook)
Dim ws = DirectCast(wb.Worksheets(1), Excel.Worksheet)
'Add Headers
For ColumnIndex = 1 To dt.Columns.Count
ws.Cells(RowToStartAt, ColumnIndex) = dt.Columns(ColumnIndex - 1).Caption
Next
'Write data to Excel
For dtRow = 0 To dt.Rows.Count - 1
RowToStartAt += 1
Dim xlColumnIndex = 1
For Each dtcolumn As DataColumn In dt.Columns
ws.Cells(RowToStartAt, xlColumnIndex) = dt(dtRow)(dtcolumn)
xlColumnIndex += 1
Next
Next
wb.Save()
wb.Close()
xl.Quit()
End Sub
The magic happens in happens in the Linq query where we group by Column A and select the Max from Column B. Then it is a simple loop through the returned enumerable to fill a new DataTable that is passed to Excel for saving.
Private Sub OPCode()
Dim dt = GetExcelData()
Dim e = From row In dt.AsEnumerable
Group By TValue = row.Field(Of String)("Column A")
Into Ts = Group, Max(row.Field(Of Double)("Column B"))
Select TValue, Max
Dim Newdt = dt.Clone 'Copies structure but not data
For Each row In e
Newdt.Rows.Add({row.TValue, row.Max})
Next
DataGridView1.DataSource = Newdt 'Just checking if we got the expected data
Dim WhereToAdd = dt.Rows.Count + 3 'Two rows down from original data
SaveDataTableToExcel(Newdt, WhereToAdd)
MessageBox.Show("Done")
End Sub