Cannot 'empty' A DataTable And Corresponding Datagridview
Jun 22, 2009
I have a datatable dimensioned as new.I add the columns that I need (during the form's load) I have a datagridview as on object on my form and set the datatable as its source.The table is loaded with values and they display properly.The User closes the form and returns to the 'Main' form. At this point no problems, everything is working great. NOW...The user re-opens the form containing the datagridview It has the values from the previous time it was open, plus the new values ! I have tried several things so when the user goes back into the form it only has the new values, but it always keeps the previous values and appends the new values to it. I have attempted to clear it by adding a line: datatable.rows.clear(); I have activily gone through the datagridview one row at a time and use a statement to clear the cells;
For Each DGVRow As DataGridViewRow In Me.DataGridViewErrorList.Rows
DGVRow.Cells.Clear()
Next
so far no luck.
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May 28, 2007
Is there a simple way to assign a populated datatable's columns to another empty datatable? That is, I want to copy a datatable's structure only but not its data.
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Apr 7, 2012
I'm trying to copy one row from DataTable to another, I looked almost everywhere and I can't find a reason why this is happening, I'm using ImportRow and still the New DataTable is empty. Here's one of the answers similar I found and It's still not working!:
Dim newTable As New DataTable
Dim dsFrom As New DataTable
For Each DBShoes In list
Dim iShoeID As Integer
[code]....
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May 14, 2009
I have a DataGridView that has some columns with dates. It binds to an in-memory Datatable which gets loaded from an string array of data passed back from the backend Some of the rows returned have nulls for the date columns. Solution 1: If I define the Date column in the DataTable as "string" I can easily convert those nulls to empty strings and display it in the grid as empty strings (desired results). However, if the user clicks on the date column header to sort by date, it doesn't order the rows as you want. You get a purely string sort order. Not acceptable
[Code]...
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May 20, 2011
I have a datagridview bound to a datatable setting its datasource property to the datatable. I would like to have a child form that contains a list of columns associated with the datatable that contains a checkbox that will allow the user to hide and show the columns ( I do not know the best control to use here) (I assume this is the easy part as All i need to do is loop through each of the datatable's columns to get the column name)
now I would like save these visible columns on some event like form_closing so that the next time the user opens the form up it will remember the settings
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Jul 30, 2009
I have several problems with rows in a DataGridView. Background information: The DataGridView (DataGridViewCalib) is in one TabPage of a TabControl, some columns of the DataGridView are automatically DataGridViewCheckBoxColumn as the DataSource have some colums which are Boolean. This is a Windows Form written in VB.Net with Visual Studio 2008. The user loads an input data file.
The problems:
1) At first arrival in the TabPage, ShowDataGridViewCalib (code below) is called. All rows are then shown in the DataGridView, despite the code saying that some rows should not be visible. Breakpoints in the code show that the code do arrive at the Rows.Visible = False events. Despite all rows beeing shown a Watch in the debugger shows that:
[code]...
There are two alternative ways of handling the rows in the code. The first attempt (commented away here) is probably the "nicest".
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Feb 7, 2011
I need to sort a DataTable or DataGridView by a column that is a string value, but with null/empty values at the BOTTOM when sorting ASCENDING. The DataTable is NOT populated by a SQL statement, so no order by. If I do
[Code]...
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Mar 5, 2009
I need to sort a DataTable or DataGridView by a column that is a string value, but with null/empty values at the BOTTOM when sorting ASCENDING.The DataTable is NOT populated by a SQL statement, so no order by.If I doDataGridView1.Sort(New RowComparer(System.ComponentModel.ListSortDirection.Ascending))then it throws an exception, saying that the DataGridView is DataBound, which is correct, but doesn't help me, and I want to keep it databound.
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Oct 3, 2010
i have a Datagridview on my forum and when i Populate it it auto creates a empty row at the end of the grid... i have looked online and seen a few post about it but nothing seams to work... i have tryed...
DataGridView1.AllowUserToAddRows = False
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Apr 23, 2010
i'm using vb 2005.I have a datagridview binding to a datatable, and user can add new rows to it. i want to enable copy and paste, so i broke the clipboard content into string array, and tried to fill the values in the datagridview.
I had problems when i had to add new row to the datagridview. because if the user clicks the last row (*) to paste the content, i need to add new row to the datatable, however, the current row is also a new datagridview row. If i just use the following code
'dgv is the datagridview
'dt is the binding table
dt=dgv.datasource
iRow = dgv.CurrentCell.RowIndex
[Code]...
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Apr 6, 2009
I use a datagridview where the rowheaders frustratingly stay blank after I load the form. If I modify/add/delete anything the rowheaders pop up. then when I sort by clicking on a columnheader the rowheaders become blank again. all these actions (load/add/modify/sort) go through the same refresh function. I can't seem to figure out why the rowheaders sporadically show up. they should stay visible all the time. btw, datagridview.refresh() doesn't work
[Code]...
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Apr 16, 2011
How can I set a datagridview control to not add a new empty row when I add an entry?
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May 20, 2010
I have the following code and I want to say that if the datagridview - dgvImportData is empty then say this message otherwise say the other message.
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Jan 20, 2011
At the moment I have a DataGridView (bindet to a DataTable) and some labels. If DataGridView's event SelectionChanged occurs,the labels should be filled with the information of the selected row -> No problems.But if I sort the DataGridView and click on a row, the informations in the labels are wrong.
Event:
Private Sub DGVMain_SelectionChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles DGVMain.SelectionChanged
If DGVMain.SelectedRows.Count > 0 AndAlso Not Me.DGVMain Is Nothing Then[code].....
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Dec 8, 2010
My application must display some data in Datagridview (status of COM ports communication) and i Used .mdb databases before for faster search and Datagridview update. How i understand Datagridview is importing data from DataTable and data in DataTable is imported from .mdb file, so i decided to make shortcut - stop to using .mdb file (data must be erased every time application start and it is useless make .mdb file and erase it every time, becouse it is increasing even when drop is used) and using only DataTable..
I want to row in Datagridview change it color to red when it's Collumn(6).text countains %error% string..
When Error in COM port is starting, i can fast find row in DataTable for that port and write information that Error accured for that port and DataGridview automatically updates:
Dim RRow as () DataRow
RRow = ds.Select("Port = 'COM3')
RRow(0).Item(6) = "Error Opening COM3"
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Nov 15, 2009
I key-in data from textbox to datagridvie..........the date data the format datatable is:
[Code]...
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Mar 4, 2011
I've been searching around a lot to figure this out. I found some code that sort of works:
VB.NET
If String.IsNullOrEmpty(CStr(Me.dgvList.Rows(i).Cells(0).Value)) Then
End If
[code].....
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Jun 2, 2009
I have a DataGridView to which I've set a list of objects to the DataSource. (I'm in VS 2005 using VB.) I created the DataGridView by creating a Data Source of type AssetIdentifier and dragging that Data Source onto my form. I want to update the DataGridView when the selection in either a combo box or another DataGridView changes. (Below I'm considering a click in another DataGridView.)
The following works:
Public Class dlgShowAssets
' class member variable
Private assetIdList As List(Of AssetIdentifier)
' pertinent subs and functions
Private Sub RefreshAssetIdentifierDataGridView()
[Code] .....
In this case, I always knew that assetIdList would have at least one element. I'd update the list, and reset the data source of the DataGridView to that list, and all was well. When I applied this to another situation, for which I couldn't guarantee that the list would have at least one element, things would work fine as long as I had at least one element in the list, but if the list became empty, the DataGridView threw System.IndexOutOfRangeException a number of times.
The rows in the DataGridView would not go away if I went from a non-zero number of elements to zero. I tried a workaround, which was to remove all of the elements, add one "dummy" element, and then re-bind the list to the control and it still didn't work. Also, following all of those exceptions, I'd get other similar exceptions when I hovered over the cells in the DataGridView. Some of the members of AssetIdentifier were "Nothing" but I fixed that in the constructor, and the exceptions still occur.
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Jan 22, 2010
[Code]....
IF cursor leaves column 0 and row 0 then it displays msgbox but I want to check where column 0 and row 0 has value or empty In case of empty cell it must display msg as
msgbox("this is empty cell")
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Jun 21, 2010
I just want to know on how will I add a Checkbox in each row of my datagridview. First I used a datatable to get all the values from my database and then pass it all to the datagridview. What I want to happen is at the first column of my datagridview there is the checkbox.[code]
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Feb 3, 2012
i build a datatable in DataGridView. When form open datagridview point to current row is first row
when i call this code :
MsgBox(dgvName.CurrentRow.Cells("drID").Value)
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Jun 21, 2010
I'm selecting value from my database, passing it to datatable then giving DataGridView.DataSource value of datatable.The thing is that in those rows i'm also selecting some dates and problem is that my default date in database is '1900-01-01 00:00:00' because i use "smalldatetime". And what i want is this...when I find default value in database i want to show it like an empty string, like i said...because date is in smalldatetime format i can't do this in SQL query so i wonder how can I change this in DataTable or even better in DataGridView...of course, in code?
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May 21, 2012
I managed to Convert a Datagridview to Datatable, Now problem is the programmatically addded Columns Seem to end up at the end of the of the initial table layout[code]...
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Jun 30, 2010
I am trying tomodify the following code from a datagrid to a datagridview but I'm not sure about how to do the conversion. The problem lies with theDataGrid.TableStyles.A dgv does not have that property.
Function
GetColumnHeadingText(ByVal
Column As
[code].....
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Sep 28, 2011
I developed a windows forms app, using VisualBasic in VS 2010. In my form, first I declared a variable as DataTable (Dim VarTable as New DataTable).
Second, changed the DataSource property of my DataGridView (DataGridView1.Datasource=VarTable)
Third, I filled the VarTable in this way: using a resulset from SqlDataReader, i added row by row.
Dim Result As SqlDataReader=CommandSQL.ExecuteReader
Do While Result.Read()
Dim RowToAdd As DataRow
RowToAdd=VarTable.NewRow()
RowToAdd("Code")=Result("Code")
RowToAdd("Name")=Result("Name")
VarTable.Rows.Add(RowToAdd)
Loop
Fourth, after the user changed data in datagridview, I saved the data back to SQL, cleared VarTable (VarTable.Rows.Clear()), and back to top of form to accept a new code. But here, problems begin. When I execute again the whole code described, the datagridview dont show the entire rows, and sometimes crashed with different errors. Solution? Dont fill VarTable row by row. Use VarTable.Load(Result) to populate the VarTable. I don't know why now works, But just I wanted to share this information.
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May 21, 2010
How to copy all datagridview data into a datatable ?
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Mar 29, 2011
I have a BackGroundWorker that produces a DataTable which is then bound to a DataGridView.
I want to have selected rows of the DGV colored based on the value of a column within the DataGrid (1 if coloured)
How can I set the row color while populating the datatable? Or do I have to set the color on the DataGridView after binding it to the datagrid?
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Oct 27, 2009
me how to bind the dataTable to dataGridView??
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Nov 12, 2009
If I have a datagridview's datasource set as some datatable, is there a quick and easy way to reflect the changes in the datatable that have been made in the datagridview?
When I sort my datagridview, the rows in the datagridview and the datatable no longer match up.I know I can catch when the dgv is sorted and for-loop through the dgv and send it to the datatable, but I was hoping there was a save/update method or some such thing.
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Apr 4, 2012
I am using the DataGridView for editing data, but when I go to access the DataTable bindings there are no data. I used to bind the following
'Data Loading
dtDettaglio = lettura_art
bsDettaglio = New BindingSource(dtDettaglio, Nothing)
dgDettagli.DataSource = bsDettaglio
dgDettagli.AutoGenerateColumns = False
[Code]...
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