I'm using VB.NET to make a stand-alone executable containing an unbounded DataGridView.
One of its columns is a combobox. I add rows to the combobox with some simple code
like this:
For r As Int16 = 0 To eachLine.GetUpperBound(0)
Dim dgvcbc As DataGridViewComboBoxColumn = grd.Columns(col)
' Errors: dgvcbc.Items.Clear()
dgvcbc.Items.Add(eachLine(r))
Next r
Works great the first time, but when I try to clear it, in order to add some different
items in the combobox, I get this error 100s of times:
> DataGridViewComboBoxCell value is not valid
Any ideas on how to fix this and why it occurs?
The issue is that, if you clear the Items in that column, every cell in that column becomes invalid. Every value in that column has to match one of the items in the drop-down list and, if there's no items, no value can be valid. It doesn't make sense to clear the drop-down list. You must leave at least the items that match the values in the cells of that column.
Related
I have the following pair of combobox that are used for two inserts in two different access tables from a single form.
The problem I have is that I am not able to make anything else load the form is selected both in Name_OT and in Year the first value that contains corresponding combobox.
I think the solution is with:
Combobox1.Selected (0) = True 'First value
But the combobox goes blank, no text or anything appears.
Solved with this
Cuadro_combinado79 = Cuadro_combinado79.ItemData(0)
Cuadro_combinado85 = Cuadro_combinado85.ItemData(0)
I have an MS ACCESS Combo Box and I wish to change the value of one of the columns in a particular row. I get error "object required" when I run this line:
Me.ComboName.Column(12, intUseRow) = myVar
(If I am unable to use the above syntax then you should also know that the row I am trying to change is always going to be the "current" visible row so there may be another way of solving the problem due to this fact).
Thanks!
If you have a recordset that is bound to a Table/Query, you will need to change the underlying data then requery the combobox to see changes.
If you load it manually (like in the form load event) and have the comboBox Row Source Type to "Value List" - you should be able to update it like this:
Copy all the data from the selected row into variables.
Combobox.RemoveItem (selected index)
change the required variable to the new value.
construct the semicolon separated string for the value list entry
combobox.AddItem new-string.
a bit messy, but it works correctly!
I have set a combobox to be visible in column1 of my Datagridview. Now I'm trying to fill same row of Datagridview where Combobox appears, from Combobox_Key_Down event. This is my code for showing combobox:
Private Sub My_DGV_CellMouseClick(sender As Object, e As DataGridViewCellMouseEventArgs) Handles MY_DGV.CellMouseClick
If e.RowIndex >= 0 Then
With My_DGV
If .Columns(.Rows(e.RowIndex).Cells(e.ColumnIndex).ColumnIndex).Name = "Column1" Then
.CurrentCell = .Rows(.CurrentRow.Index).Cells(.CurrentCell.ColumnIndex)
Show_Combobox(.CurrentRow.Index, .CurrentCell.ColumnIndex) 'function that shows my Combobox in that cells
Combo.Visible = True
Else
Combo.Visible = False
End If
End With
End If
End Sub
I tried many things, but I don't know how to determine in which row Combobox appears and how give that Datagridview row my Combobox values. Someone please give me a clue of what should I do. Thanks in advance !
The first problem with your approach is that the DGV can have only one DataSource: it can either show the m:m association table or the related elements. If you include columns from one of the tables into the query for display, the table becomes non updatable and users can be confused why they cannot edit something they can see. It seems of little value they way you describe it, since they cannot see the detail data until after they make a selection.
Next, it requires another datatable to supply the details for CboColB. Since you want the DGV bound to a DataTable easy updates, you end up having to poke data into cells over and over.
Finally, consider what the user is confronted with. Using a Country table (200+ countries/locales with ISO code and name) and a list of flag colors, a table for CountryFlagColors will have hundreds and hundreds of rows (at just 2 colors per flag).
A better display might be to filter the m:m table (flagcolor) to a selected item so the user is only confronted with the data subset they are currently interested in:
The datatable used in the DGV is built from the m:m table:
The Country column is hidden.
When they choose from the CBO at the top, that is used as a RowFilter to limit the rows to the relevant ones.
In the RowValidating event, when the country cell is DBNull, copy the SelectedValue from the country combo to the DGV cell to fill in the blank
I would probably really make the user click a button and manually add a row so I could seed the country value then rather than depend on events.
It uses a DataAdapter and after adding X number of flag definitions, da.Update(dtFlagColors) applies/saves all the changes.
Ok, so that provides the core functionality to assign N color selections to define the flag colors for a country. The missing element is the 'details' for the Color item.
I added a meaningless int and string item to the Color table, one way to display these would be to create an alias in the SQL with the important details. Displaying them as discrete elements can either make the query non updatable or invites the user to edit things they cannot edit here. My silly SQL:
"SELECT Id, Name, Concat(Name , ' (' , intItem , ' ' , stritem,')') As Info from FColor"
Then use 'Info' as the display member on the CBO column in the dgv:
dc = DirectCast(dgvCF.Columns(0), DataGridViewComboBoxColumn)
dc.DataSource = dtFlagColors
dc.DisplayMember = "info"
dc.ValueMember = "id"
dgvCF.DataSource = dtSample
The combo column has its own datasource of course, in order to display one thing and use another for as the Value to give back to you. Result (the values are silly):
It is not exactly what you want, but comes close and is much simpler. It also requires almost no code for driving the associative entity. Another alternative would be to use a DGV as the second picker so you can show the extended data and manually add rows to a DGV:
If you set the dropdown style to Nothing, it looks like a text column.
I am having some trouble with a sorting an unbound DataGridView. I am filling a DataTable from a StreamReader, and then manually transferring the items from the DataTable to the DataGridView. The AllowUserToAddRows property is set to true on the DataGridView.
This populates the DataGridView, without any trouble. I can sort the columns by clicking on the column headers without any issue. If I add a value to the first column in a new row, and then try to sort the column, I get an error message that shows: "Object must be of type String."
I have tried different ways of converting all of the cells in the column to the same datatype, but I cannot get around this issue. Am I missing something here?
In the form load event, I have the following code:
dgvStartingGrid.Columns(0).ValueType = GetType(Integer)
I also am making sure that the values from the StreamReader are Integer types before entering them in the DataGridView:
If IsNumeric(strColumnValue) Then
dtbFillGrid.Rows(intCurrentRow).Item("Starting Position") = strColumnValue
End If
I have also tried:
dtbFillGrid.Rows(intCurrentRow).Item("Starting Position") = CInt(strColumnValue)
What could cause this issue? I have verified that all of the cells in the column are of the same datatype, but it still gives me an error, and I am sure that it is this column that is the problem.
The other columns are of string type, and I do not have any issue sorting them by their column headers, unless I click the first column, and then the exception is thrown.
Right, after some testing I found this out.
Even though you have set your DataGridView column to be Integer it doesn't mean that it will be filled with Integers. Unless you alter the datatype of the DataTable the DataGridView is actually filled with strings. The sorting function on a DataGridView is not based on column type, it is based on the first value it finds. And since you that value is a string, you get an error when it reaches your typed value (which is an Integer).
So here is what you have to do.
dtbFillGrid.Columns.Item(0).DataType = GetType(Integer)
Where 0 is the column containing Integer.
I have two ComboBoxes on my userform. The first provides options from a named list 'Category'. I typed the word Category into the row source for this ComboBox and it works fine offering drop down for all items on the Category list.
Each item on the Category list is itself a named range. I would like the second ComboBox (Supplier) to read the item selected in the first and then offer the options within the named range that is selected. At the moment it only offers the first item in each named range. I am currently using the following code for the first ComboBox.
Private Sub Category_Change()
Worksheets("Input").Range("D10") = Category.Value
'Worksheets("Input").Range("D10") = CStr(Worksheets("Input").Range("D10"))
Supplier.RowSource = Worksheets("Input").Range("D10")
End Sub
This writes the value selected for the first ComboBox to a cell and then attempts to get the second ComboBox to read this...
Any help would be magnificent!
Josh
You need to get the range specified by the text in cell D10, not just get the range D10.
change your code to:
Supplier.RowSource = Range(Worksheets("Input").Range("D10").Value)
Thanks guys. I believe you were all correct. Purely by chance I stumbled upon the cause of my problem.
My primary list was written as a column- RowSource read it fine.
My secondary lists were all written as rows- which RowSource was only pulling the first item from. Rearranging the rows to columns and updating Name Manager sorted it.
What an irritating answer...
Thanks again!