[RESOLVED] DataGridView: Can we find a cell by its first column?

[pourkascheff]

First of all is there any DGV snippet or its examples in codebank? I'd be grateful if you redirect me there.

Consider you have a long list of string matrix (No datasets and no dbs, just manual CSV written values) and you want to find/locate/search a specific row while "sort" is open for user to manipulate the entire table. But once you want to change a cell value formerly you did this:

DataGridView1.Item(VCol, VRow).Value = (TrackBar1.Value).ToString

But since user reordered the table cells (not as sorted as I did before) How can we find first column (ID of then entire row) then tell it to change row number VRow?

1) I was thinking about a for loop to start from the beginning of the table to its end to find exact ID we are looking for (Something like .FindStringExact in ListBox) then updating its cells. But come on... This is Visual Studio, it should be a proper (and in most cases an easier) way to do that, Aye?
2) Is there a "filter" kind of search (Like a built-in one in DevExpress GridControl but this is a very different complex control and in my opinion ≠DGV) to fine a specific line? (Not by removing/hiding other lines but to automatically scroll horizontally to find a line) some sort of "Go To Line" function?

[jmcilhinney]

The fact that you're not using a database doesn't mean that you can't use a DataTable and a BindingSource.

[pourkascheff]

What do you mean?
In all tutorial videos they all connect it to an access file online on the network, username and password required, after model creating wizard... (This user is taking shelter in his comfort zone, please take him out with making the story look safe)

[wes4dbt]

Lots of examples, more than one way to do it, just Google "visual basic create datatable from csv file"

[techgnome]

Lotsa options here....
https://search.brave.com/search?q=vb...source=desktop


-tg

[jdelano]

How do you want to have the user edit the cell? Will the edit then be written to the source CSV file? If so, the fact that they sorted the column doesn't affect the ID of the row (does your CSV have a unique ID per row?)

I downloaded the 100-record organization csv file from here https://www.datablist.com/learn/csv/...mple-csv-files. I filled the grid with the file data, the grid allows for editing, when the user finishes editing it writes the new value to a temp file that is then renamed as the source file.

I'm sure there is a better way to go about this, but ...

   Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click


        Dim TextFieldParser1 As New TextFieldParser("F:\temp\organizations-100.txt")

        TextFieldParser1.Delimiters = New String() {","}

        While Not TextFieldParser1.EndOfData
            Dim Row1 As String() = TextFieldParser1.ReadFields()

            If dgvData.Columns.Count = 0 Then
                Dim i As Integer

                For i = 0 To Row1.Count - 1
                    dgvData.Columns.Add(Row1(i), Row1(i))
                Next
            Else
                dgvData.Rows.Add(Row1)
            End If

        End While

        TextFieldParser1.Close()

    End Sub

    Dim prevCellContents As String

    Private Sub dgvData_CellBeginEdit(sender As Object, e As DataGridViewCellCancelEventArgs) Handles dgvData.CellBeginEdit
        ' save what the data in the cell was before the attempted it
        prevCellContents = dgvData.CurrentCell.Value
    End Sub

    Private Sub dgvData_CellEndEdit(sender As Object, e As DataGridViewCellEventArgs) Handles dgvData.CellEndEdit

        Dim currentCellContents As String = dgvData.CurrentCell.Value
        Dim rowID As String
        Dim changedFieldIndex As Int16

        If currentCellContents <> prevCellContents Then
            ' the cell changed
            rowID = dgvData.Item(0, dgvData.CurrentCell.RowIndex).Value
            changedFieldIndex = dgvData.CurrentCell.ColumnIndex

            If UpdateCSVFile(rowID, changedFieldIndex, currentCellContents) Then
                MsgBox($"You changed the value from {prevCellContents} to {currentCellContents}")
            Else
                ' the save failed, put the old value back in the cell
                dgvData.CurrentCell.Value = prevCellContents
            End If
        Else
            MsgBox("Edit has been cancelled")
        End If

    End Sub

    Private Function UpdateCSVFile(recID As String, columnNumber As Int16, newValue As String) As Boolean

        Try
            Dim rwNumber As Long = 0
            Dim parser As New TextFieldParser("F:\temp\organizations-100.txt")   ' open the source file
            parser. Delimiters = New String() {","}

            Dim tempFile As New StreamWriter("F:\temp\temp.txt")   ' create a temp file
            Dim tempFileFields As New List(Of String)
            Dim foundID As Boolean

            While Not parser.EndOfData
                Dim fields As String() = parser.ReadFields()

                ' if the record id matches, replace the value - we know the id field is in the first field
                foundID = fields(0) = recID
                Dim fld As String
                For i = 0 To fields.Count - 1
                    fld = fields(i)
                    If fld.IndexOf(",") > 0 Then
                        ' the field itself contains a comma, it must be surrounded by """" to write correctly
                        ' with streamwriter
                        If foundID And i = columnNumber Then
                            ' this is the line that has the edit field value
                            fld = """" & newValue & """"
                        Else
                            fld = """" & fld & """"
                        End If
                    Else
                        If foundID And i = columnNumber Then
                            fld = newValue
                        End If
                    End If
                    tempFileFields.Add(fld)
                Next

                tempFile.WriteLine(String.Join(",", tempFileFields))   ' write the line of data to the temp file
                tempFileFields.Clear()
            End While

            parser. Close()
            tempFile.Close()

            ' rename the old file as a backup with date time stamp
            ' rename the temp file as the file name
            Dim dateTimeStr As String = Format(Now, "MMddyyHmmss")
            My.Computer.FileSystem.RenameFile("F:\temp\organizations-100.txt", $"organizations-100-{dateTimeStr}.txt")
            My.Computer.FileSystem.RenameFile("F:\temp\temp.txt", "organizations-100.txt")

            Return True
        Catch ex As Exception
            MsgBox($"Save failed. {ex.Message}")
            Return False
        End Try

    End Function

this is a play around form, ignore the date control. The file is loaded: https://imgur.com/42B84eJ, I sorted by the "Founded" field and entered edit mode (press f2 or dbl click the cell) https://imgur.com/NfWBxed, I changed the year and pressed enter. https://imgur.com/k0xb2gf - it renames the old file (to create a backup) and renames the temp file to the original file name https://imgur.com/qfq5954, the new file after the edit https://imgur.com/4WfsNNi, the original file saved as a backup https://imgur.com/M1s9r7L

The key is you need well, a key for each record in the CSV file.

[jmcilhinney]

What do you mean?

I mean that you can still use a DataTable even if you're not using a database. DataTables are often used with databases because they are basically made to behave like an in-memory database table but they are just a thing that contains data so that data can come from anywhere you want it to.

In all tutorial videos...

Maybe you should start thinking for yourself a bit instead of just painting by numbers. If you can add a new row to a DataTable in order to save it to a database, why can't you add multiple new rows to a DataTable for other purposes?

[pourkascheff]

Thanks all for contribution...