DataGridViewComboBoxColumn doesn't show data until clicked in a datagridview control

[Dave Kreskowiak]

It's strange that you're using a Combo to show/pick the price of a product. Normally, a combo is used to pick from a standard list of items where the ID of an item in the list corresponds to an ID column in another table. For example, a list of team IDs and Names in one table and a schedule table, listing two teams ID's, instead of names. The combo would show you the team names (DisplayMember), but the value (ValueMember) of each name in the list returns that teams ID. This ID would be populated into the schedule table (DataPropertyName). For this to work you need two binding sources. One bound to the schedule data and one bound to the team data. For example, there are two BindingSources, one called MasterScheduleBindingSource, which the DataGridView is bound to is bound to a table containing the data for the schedule, and a second TeamsDataBindingSource, which will be used by the combo and is bound to a table with TeamId's and names.

Dim comboColumn As New DataGridViewComboBoxColumn
With comboColumn
' Column header that shows up in the DataGridView
.HeaderText = "Home Team"

' This is the column name in the MasterScheduleBindingSource where team ID's are going to get stored.
.DataPropertyName = "HomeTeamId"

' This is the binding for the combo to it's data
.DataSource = TeamsDataBindingSource
.ValueMember = "TeamID"
.DisplayMember = "TeamName"

End With
MyDGV.Columns.Add(comboColumn)

A guide to posting questions on CodeProject[^]
Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
     2006, 2007, 2008

[SteveNY]

I do have two binding sources. One binding source for orders and one for prices. I used a combobox so user can select a price from available prices but I'm open to suggestions for other controls to use.

[Dave Kreskowiak]

SteveNY wrote:

I do have two binding sources. One binding source for orders and one for prices.

Then you've got something else set somewhere or some other code you haven't shown us screwing this up for you.

SteveNY wrote:

I used a combobox so user can select a price from available prices but I'm open to suggestions for other controls to use.

Normally, a textbox does this. You usually don't find a one-to-many relationship between products and prices.

A guide to posting questions on CodeProject[^]
Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
     2006, 2007, 2008

[SteveNY]

I think you're misunderstanding my problem. It's not that the data isn't showing up. It's the fact that I have to click the column multiple times in order for the data to show up. My code to initialize the column is the same as you've posted. I made a separate demo app to show what I mean. I put a datagridview on an empty form and in the form's load event I have this code: Dim nameComboBoxColumn As New DataGridViewComboBoxColumn With nameComboBoxColumn .HeaderText = "names" .Items.Add("john doe") .Items.Add("jane doe") .DisplayStyle = DataGridViewComboBoxDisplayStyle.Nothing End With DataGridView1.Columns.Add(nameComboBoxColumn) When the app loads the data is not shown in the column until I click the column.

[Dave Kreskowiak]

SteveNY wrote:

It's not that the data isn't showing up. It's the fact that I have to click the column multiple times in order for the data to show up.

I understand that. Since there isn't enough information to figure out what you did wrong, I supplied the template of how to do it right.

SteveNY wrote:

I made a separate demo app to show what I mean. I put a datagridview on an empty form and in the form's load event I have this code: ... When the app loads the data is not shown in the column until I click the column.

I can't duplicate the problem. There's something else you're doing that you haven't mentioned.

A guide to posting questions on CodeProject[^]
Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
     2006, 2007, 2008

[javedk09]

try to solve the issue with the microsoft benchwork regards, Javed Ahmed Khan

[SteveNY]

I haven't done anything more than what I described. I used camtasia to record the construction of a simple project from scratch. I did the same as last post, datagrid view on form, made a column, added items to column, added column to dgv. Here is the shockwave video from camtasia: http://www.matcmp.ncc.edu/~steve/vb/comboboxproblem/comboboxproblem.html[^]

[Dave Kreskowiak]

Your example shows the expected behavior. Since the cell doesn't have a value yet (DbNull,) one isn't selected in the ComboBox.

A guide to posting questions on CodeProject[^]
Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
     2006, 2007, 2008

[SteveNY]

OK, So how do I have the first item selected by default? I have searched on the workaround since the dgvcmb doesn't have a selectedindex property but haven't found anything I have been able to use or haven't tried. Thanks

[Dave Kreskowiak]

The cell has to have a value that matches a Value in the data bound to the Combo. In your example, the default cell value is DbNull, which the data in the Combo doesn't contain. Set the value of the cell to one of the values in the Combo and the combo will show the correct item.

A guide to posting questions on CodeProject[^]
Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
     2006, 2007, 2008