How to fill different ComboBoxes in a DataGridView control with C#?

Question

I have a datagridview with 3 comboboxes.

When in combobox 1 (=Rownumber = 1) AA is selected then at runtime combobox2 has to be filed with some value.

This value is comming from a DataTable.

When some value is selected in combobox2 (Also RowNumber = 1), then at runtime combobox3 (also RowNumber = 1) has to be filled with some value also comming from a DataTable.

Above means that when combobox1 where the columnindex is 0 has the value:

AA

BB

CC

When AA is selected ComboBox2 where the columnindex is 0 must have the value (ComboBox2 is must be filled at runtime and the values are comming from a DataTable):

11

22

33

When 11 is selected ComboBox3 where the columnindex is 0 must have the value (ComboBox3 is must be filled at runtime and the values are comming from a DataTable):

Name

LastName

Address

City

THEN THE NEXT ROW

At RowNumber 2 ComboBox1 has the value:

AA

BB

CC

when BB is selected, ComboBox2 also at RowNumber 2 must have the value (ComboBox2 is must be filled at runtime and the values are comming from a DataTable):

Pipo

Peppie

Clown

when Pipo is selected, ComboBox3 also at RowNumber 2 must have the value (ComboBox3 is must be filled at runtime and the values are comming from a DataTable):

Yes

No

Maybe

I have tried a lot but nothing works.

Is above possible and how in C#?

Remco van Heck · Answer

The problem is that it's not easy to use this bounds! The problem is that on every row there is another bind. This is what it make it impossible. After reading a lot on the internet the only conclusion I can make that it is impossible to do what I want.

Sam Hobbs · Answer

I am sorry I can't help much but I think you are describing cascading data sources. Look for articles in this web site about that. It is relatively easy to do using bound controls but you need to learn about bound controls if you do not already know. You did not state explicitly if you are using bound controls. If you are not using bound controls then the solution seems easy to me; you just need to handle the event of the selection changing for each ComboBox; do you know how to do that? Using bound controls generally speaking you need to handle the event of the selection changing from a ComboBox and in the handler function set a filter (see BindingSource.Filter Property) for the data source for the next ComboBox. So when ComboBox1's selection changes set a filtter for ComboBox2 and clear ComboBox3 or something like that.

Remco van Heck · Answer

Since there is no answer to this problem I have to make 50 dgv each exist out of 1 row. I fill them dvg by dvg.

Remco van Heck · Answer

Yes I read the link but this isn't the solution. Here are rows are removed and then added. But the rows are already existing and they can't be removed because the previous has already values.

Suthish Nair · Answer

did you refer the link that also not helped?

Remco van Heck · Answer

This doesn't work --> dataGridView1.Columns.Insert(0 ComboBoxDB);

Suthish Nair · Answer

am not sure.. try.. also refer links private void dataGridView1_SelectionChanged(object sender EventArgs e) { if (dataGridView1.CurrentCell.ColumnIndex == 0) { } }

Remco van Heck · Answer

Just to clarify my understanding is that you don't know how to make a certain selection of the combobox items get the proper data from your database (algorithm-wise not syntax-wise). I'm really sorry for all the confusion if that's not true. You understood it wrong. It is clear to me how to fill a combobox What I don't know is how to fill them differently each row. So as in my example: row 1 --> combobox1 has the value abc def hij --> combobox2 has the value table1 table2 etc... (when abc is selected in combobox1) combobox3 has the values: name address etc... (when table1 is selected in combobox2) row2 --> combobox1 has the value abc def hij --> combobox2 has the value TV Radio Laptop etc... (when def is selected in combobox1) combobox3 has the values: button speaker etc.. (when Radio is selected in combobox2). So putting values/items into a combobox is not the problem but putting different comboboxes in each row is.

Jure · Answer

I don't know much about your project but from what you've said I assume you have a lot of data so if you don't want to torture yourself (bad code is bad for your mental state - think about maintenance) you should make things organized and I think MVC pattern suits well here. I'm wet behind ears myself but I'm sure someone much more experienced will tell you too that it's good to separate GUI data and the connection between GUI and data. Just to clarify my understanding is that you don't know how to make a certain selection of the combobox items get the proper data from your database (algorithm-wise not syntax-wise). I'm really sorry for all the confusion if that's not true. It might help if you upload your project and a sample of your database. About putting items into combobox use Items property which is a collection-type: my_combobox.Items.Add(...); my_comboboc.Items[0] = ... ..etc..

Remco van Heck · Answer

You need a good design first something that will dynamically populate your comboboxes and your datagridview and I think delegates can be useful here. Think of delegates as function variables. You can use them anywhere (not that you should). I still don't see why to use delegates and why a good design? It's simple to put a DataTable in a Combobox and the design is clear because there are a few databases with tables and this tables has columns nothing more nothing less. Also with Delegates please explain me how to put values in each Combobox because that's where the difficult is. If I know how then I can also populate them with the values from my DataTables.

Jure · Answer

You have a LOT of combinations to worry about over 1000 (10+ items per combobox). You need a good design first something that will dynamically populate your comboboxes and your datagridview and I think delegates can be useful here. Think of delegates as function variables. You can use them anywhere (not that you should). In my opinion you should really focus on the algorithm first leave the practical stuff such as filling your datagridview for later. I myself would implement model-view-controller pattern.

Manikavelu Velayutham · Answer

Then its very simple to implement in Javascript. You can achieve this using JSON call. Based on the first combo box selection JSON call will hit the database and file the second combo box.

Remco van Heck · Answer

May I Know how many items will be there in the combo box approximately ? I can't say It depense on how many tables a database has. Because it show's the name of the tables and after selected on of the tables it shows the columns. I think that companies don't have databases with more than 200 tables so say the values will between 1 and 200.

Manikavelu Velayutham · Answer

May I Know how many items will be there in the combo box approximately ? Becuase if the items come around 100 to 200 we can have it in array. Based on the selection we can select or fill the items in other combo box using the normal javascript.

Remco van Heck · Answer

I can't use delegates because the values are comming from a DataTable from a database. This also means that some Comboboxes has more then 3 values normally did will be more then 10 values for every Combobox. The above was an example to make the question clear without to much overhead. I tried code like this --> dataGridView1.Columns.Insert(0 ComboBoxDB); dataGridView1.Rows[rowNr1].Cells[colNr + 1].Value = Convert .ToString(cmbBox.SelectedIndex); What ever I tried It doesn't work so please send me code how to do it. I only think that it's not possible what I want? But if you think it's possible please let me know.

Jure · Answer

Have you tried using ComboBox's SelectedIndexChanged event? I've done something very similar before where I displayed a different set of controls depending on which option the user chose. But be careful when writing the whole thing... For example 3 options in each ComboBox will give you 27 different combinations. This can quickly turn into a spaghetti code so I recommend you to use custom delegates or events and separate code heavily into functions to avoid any copy-pasting and to make it possible to dynamically construct one large function out of little ones. This article might help you with evaluating multiple variables but I don't recommend making a switch with 27+ cases. Upload your project if you get stuck.