I'm doing a project in vb and I'm trying to add all the rows in dataTable name dt to a new dataTable name dtNew but i dont want duplicate rows to be added in dtNew instead adding the count if its duplicate. someone help me please.
here is a sample dataTable name dt as you can see apple is duplicate
here is my code.
Dim dtNew As DataTable = New DataTable '---> I Created new DataTable
'---> Created 3 columns
dtNew.Columns.Add("TYPE", Type.GetType("System.String"))
dtNew.Columns.Add("NAME", Type.GetType("System.String"))
dtNew.Columns.Add("COUNT", Type.GetType("System.Int32"))
For Each dtRow As DataRow In dt.Rows ' ---> loop all the rows in dt DataTable
Dim newRow As DataRow = dtNew.NewRow
newRow("TYPE") = dtRow("TYPE")
newRow("NAME") = dtRow("NAME")
newRow("COUNT") = dtRow("COUNT")
'check if dtNew DataTable has no row
If Not dtNew Is Nothing AndAlso dtNew.Rows.Count = 0 Then
'add new row
dtNew.Rows.Add(newRow)
Else
' I want to check first all the rows in dtNew DataTable
' if its existed, and if it's not then add new row
For Each dtNewRow As DataRow In dtNew.Rows
If ((dtNewRow("TYPE") = "VEGETABLE" OrElse _
dtNewRow("TYPE") = "FRUIT") And _
dtNewRow("NAME") <> newRow("NAME")) Then
'insert row
dtNew.Rows.InsertAt(newRow, dtNew.Rows.Count)
'error: Collection was modified; enumeration operation might not be executed.
End If
Next
End If
Next
For Each row As DataRow In dt.Rows
Dim type = CStr(row("Type"))
Dim name = CStr(row("Name"))
Dim existingRows = dtNew.Select(String.Format("Type = '{0}' AND Name = '{1}'",
type,
name))
If existingRows.Length = 0 Then
'No match so create a new row.
Dim newRow = dtNew.NewRow()
newRow("Type") = type
newRow("Name") = name
newRow("Count") = row("Count")
dtNew.Rows.Add(newRow)
Else
'Match found so update existing row.
Dim newRow = existingRows(0)
newRow("Count") = CInt(newRow("Count")) + CInt(row("Count"))
End If
Next
As the tables have the same schema, you could even simplify the If block to this:
dtNew.ImportRow(row)
That would only be a problem if row had a RowState other than Unchanged and you didn't want to import that too.
Related
I want to choose non-duplicate elements in DataTable
Where DataTable contains data as follows
TABLE A
COLUMN A
AM1
AM5
AM6
AM5
AM1
AM1
AM1
Where the final output is datatable= AM6
MY CODE
Public Function RemoveDuplicateRowsG(ByVal dTable As DataTable) As DataTable
For intI = dTable.Rows.Count - 1 To 0 Step -1
For intJ = intI - 1 To 0 Step -1
If dTable.Rows(intI)(0) = dTable.Rows(intJ)(0) Then
dTable.Rows.RemoveAt(intI)
dTable.Rows.RemoveAt(intJ)
Exit For
End If
Next
Next
dTable.AcceptChanges()
Return dTable
End Function
Maybe if you iterate the datatable first and select the row(s) which contain the value only once, put it inside a new datatable and return the newly created datatable.
Dim dtToReturn As New DataTable
For Each row As DataRow in dTable.Rows
'Select all rows from original datatable with the same value
Dim datarow() As DataRow = dTable.Select("COLUMN A = " & row.Item(0))
'Insert to the new datatable if returned datarow collection only has 1 row
If datarow.Count = 1 Then
dtToReturn.Rows.Add(datarow)
End If
Next
Return dtToReturn
When I go to add data in first row there is empty lines that appear below my code, why do these lines appear? I need only to add data in one row and save it.
Dim pringdata As String = "SELECT * FROM itemInfo "
Dim sqlconload As New SqlConnection(sqlcon)
Try
sqlconload.Open()
Dim da As New SqlDataAdapter(pringdata, sqlconload)
ds.Clear()
da.Fill(ds, "itemInfo")
Dim rowcount As Integer
rowcount = ds.Tables("itemInfo").Rows.Count
If rowcount >= 1 Then
DGVorders.Rows.Add(rowcount)
For i = 0 To rowcount - 1
If DGVorders.CurrentRow.Cells(0).Value = ds.Tables("itemInfo").Rows(i).Item("itemCode") Then
DGVorders(1, e.RowIndex).Value = ds.Tables("itemInfo").Rows(i).Item("itemName")
DGVorders(2, e.RowIndex).Value = ds.Tables("itemInfo").Rows(i).Item("Uint1")
DGVorders(4, e.RowIndex).Value = ds.Tables("itemInfo").Rows(i).Item("price1")
End If
Next
End If
sqlconload.Close()
Catch ex As Exception
End Try
End Sub
Modify the "AllowUsersToAddRows" property to remove that blank line.
Example:
DataGridView1.AllowUserToAddRows = False
DGVorders.Rows.Add(rowcount) will add rowcount amount of empty rows to your DataGridView. I don't know why you are doing that, it's not as if you are adding values to the cells in those new rows in your for loop.
updated
If dataGridView1.CurrentRow.Cells(0).Value = ds.Tables("itemInfo").Rows(i)("itemCode") Then
Dim newRow As DataGridViewRow = TryCast(dataGridView1.CurrentRow.Clone(), DataGridViewRow)
newRow.Cells(1).Value = ds.Tables("itemInfo").Rows(i)("itemName")
newRow.Cells(2).Value = ds.Tables("itemInfo").Rows(i)("Uint1")
newRow.Cells(3).Value = ds.Tables("itemInfo").Rows(i)("price1")
dataGridView1.Rows.Add(newRow)
End If
So, quite simple.
I am importing CSVs into a datagrid, though the csv always has to have a variable amount of columns.
For 3 Columns, I use this code:
Dim sr As New IO.StreamReader("E:\test.txt")
Dim dt As New DataTable
Dim newline() As String = sr.ReadLine.Split(";"c)
dt.Columns.AddRange({New DataColumn(newline(0)), _
New DataColumn(newline(1)), _
New DataColumn(newline(2))})
While (Not sr.EndOfStream)
newline = sr.ReadLine.Split(";"c)
Dim newrow As DataRow = dt.NewRow
newrow.ItemArray = {newline(0), newline(1), newline(2)}
dt.Rows.Add(newrow)
End While
DG1.DataSource = dt
This works perfectly. But how do I count the number of "newline"s ?
Can I issue a count on the number of newlines somehow? Any other example code doesn't issue column heads.
If my csv file has 5 columns, I would need an Addrange of 5 instead of 3 and so on..
Thanks in advance
Dim sr As New IO.StreamReader(path)
Dim dt As New DataTable
Dim newline() As String = sr.ReadLine.Split(","c)
' MsgBox(newline.Count)
' dt.Columns.AddRange({New DataColumn(newline(0)),
' New DataColumn(newline(1)),
' New DataColumn(newline(2))})
Dim i As Integer
For i = 0 To newline.Count - 1
dt.Columns.AddRange({New DataColumn(newline(i))})
Next
While (Not sr.EndOfStream)
newline = sr.ReadLine.Split(","c)
Dim newrow As DataRow = dt.NewRow
newrow.ItemArray = {newline(0), newline(1)}
dt.Rows.Add(newrow)
End While
dgv.DataSource = dt
End Sub
Columns and item values can be added to a DataTable individually, using dt.Columns.Add and newrow.Item, so that these can be done in a loop instead of hard-coding for a specific number of columns. e.g. (this code assumes Option Infer On, so adjust as needed):
Public Function CsvToDataTable(csvName As String, Optional delimiter As Char = ","c) As DataTable
Dim dt = New DataTable()
For Each line In File.ReadLines(csvName)
If dt.Columns.Count = 0 Then
For Each part In line.Split({delimiter})
dt.Columns.Add(New DataColumn(part))
Next
Else
Dim row = dt.NewRow()
Dim parts = line.Split({delimiter})
For i = 0 To parts.Length - 1
row(i) = parts(i)
Next
dt.Rows.Add(row)
End If
Next
Return dt
End Function
You could then use it like:
Dim dt = CsvToDataTable("E:\test.txt", ";"c)
DG1.DataSource = dt
I'm trying to define a datarow to hold values and then add it to data set
indgv: datagridview with values in it
dsdetails: a dataset with a table named details
If indgv.Rows.Count > 0 Then
Dim dr As DataRow
dr = dsdetails.Tables("details").NewRow
For Each row As DataGridViewRow In indgv.Rows
dr("mat") = row.Cells("icode").Value
dr("dateoftrans") = Me.DateTimePicker1.Value
dr("numoftrans") = transnum.Text
dr("type") = 1
dr("doc") = doctyp.SelectedValue
dr("amount") = row.Cells("iamo").Value
dsdetails.Tables("details").Rows.Add(dr)
Next
adpdetails.Update(dsdetails, "details")
End If
running this causes the following error
Object reference not set to an instance of an object.
how to rephrase the declaration with 'New' to avoid the problen
BTW : when using new as the following
Dim dr As New DataRow = dsdetails.Tables("details").NewRow
it shows design time error
Type 'dsdetails.Tables' is not defined.
Try this code:
If indgv.Rows.Count > 0 Then
Dim tbl As DataTable = dsdetails.Tables("details")
Dim dr As DataRow
For Each row As DataGridViewRow In indgv.Rows
dr = tbl.NewRow 'Create a new row inside the loop!
dr("mat") = row.Cells("icode").Value
dr("dateoftrans") = Me.DateTimePicker1.Value
dr("numoftrans") = transnum.Text
dr("type") = 1
dr("doc") = doctyp.SelectedValue
dr("amount") = row.Cells("iamo").Value
tbl.Rows.Add(dr)
Next
adpdetails.Update(tbl)
End If
If all you need is to copy rows from one table to another, DataTable class has a Copy method you may want to use. It works like this:
Dim dtCopy As New DataTable()
dtCopy = dt.Copy()
If you have a datagridview control bound to a table, you could also use this form:
Dim dtCopy As New DataTable()
dtCopy = DirectCast(dataGridViewX1.DataSource, DataTable).Copy()
The Copy method will copy the datatable structure and the data.
If you want to copy the structure only without the data you could use Clone method.
I am using this function to create datatable from gridviews. It works fine with Gridviews with AutoGenerateColumns = False and have boundfields or template fileds. But if I use it with Gridviews with AutoGenerateColumn = True I only get back an empty DataTable. Seems Gridview viewstate has been lost or something. Gridview is binded on PageLoad with If Not IsPostback. I can't think of anything else to make it work. Hope someone can help me.
Thanks,
Public Shared Function GridviewToDataTable(gv As GridView) As DataTable
Dim dt As New DataTable
For Each col As DataControlField In gv.Columns
dt.Columns.Add(col.HeaderText)
Next
For Each row As GridViewRow In gv.Rows
Dim nrow As DataRow = dt.NewRow
Dim z As Integer = 0
For Each col As DataControlField In gv.Columns
nrow(z) = row.Cells(z).Text.Replace(" ", "")
z += 1
Next
dt.Rows.Add(nrow)
Next
Return dt
End Function
Slight modification to your function above. If the autogenerate delete, edit or select button flags are set, the values for the fields are offset by one. The following code accounts for that:
Public Shared Function GridviewToDataTable(ByVal PassedGridView As GridView, ByRef Error_Message As String) As DataTable
'-----------------------------------------------
'Dim Tbl_StackSheets = New Data.DataTable
'Tbl_StackSheets = ReportsCommonClass.GridviewToDataTable(StackSheetsGridView)
'-----------------------------------------------
Dim dt As New DataTable
Dim ColInd As Integer = 0
Dim ValOffset As Integer
Try
For Each col As DataControlField In PassedGridView.Columns
dt.Columns.Add(col.HeaderText)
Next
If (PassedGridView.AutoGenerateDeleteButton Or PassedGridView.AutoGenerateEditButton Or PassedGridView.AutoGenerateSelectButton) Then
ValOffset = 1
Else
ValOffset = 0
End If
For Each row As GridViewRow In PassedGridView.Rows
Dim NewDataRow As DataRow = dt.NewRow
ColInd = 0
For Each col As DataControlField In PassedGridView.Columns
NewDataRow(ColInd) = row.Cells(ColInd + ValOffset).Text.Replace(" ", "")
ColInd += 1
Next
dt.Rows.Add(NewDataRow)
Next
Error_Message = Nothing
Catch ex As Exception
Error_Message = "GridviewToDataTable: " & ex.Message
End Try
Return dt
End Function