DataGridViewComboBoxCell: how to set the selected value when adding a row?

Question

I have this form that allows the user to select an item (code - product) from comboxbox. enter quantity and price and add it to the list.

Loading inventory in the form

private List<Inventory> inventories = new Inventory().read_inventory(); 

Configuring ComboBox with Values

 private void set_drop_down_inventory() { cb_inventory.DisplayMember = "name"; cb_inventory.DataSource = inventories; cb_inventory.ResetText(); cb_inventory.SelectedIndex = -1; } 

When the user selects a product, he will create a new instance.

 private void cb_inventory_SelectionChangeCommitted(object sender, EventArgs e) { var selected_inventory = (cb_inventory.SelectedItem as Inventory); sales_order_detail = new Sales_Order_Detail(selected_inventory, 0); tx_description.Text = selected_inventory.description; tx_price.Text = selected_inventory.get_price_str(); } 

As soon as the user adds an item, he calls this code.

 private void btn_add_item_Click(object sender, EventArgs e) { // Set the inputted data into the instance before adding to the list sales_order_detail.description = tx_description.Text.ToString(); sales_order_detail.quantity = tx_quantity.Value; sales_order_detail.price = Convert.ToDecimal(tx_price.Text); // Adding the instances to a List sales_order.sales_order_details.Add(sales_order_detail); // Sets the Datagrid to provide the data+ initialize_datagrid(sales_order_detail); } 

This is how I initialize the datagrid because I need to manually display the columns - this is where I am not sure what to do - I believe that I do not need to manually add a new row every time the user adds an item because this datagrid is limited to List <>, so any instance is added to List <> it will be added to the grid when I run dgv.Refresh ()

 private void initialize_datagrid(Sales_Order_Detail sales_order_detail) { dgv_sales_order_details.Columns.Clear(); dgv_sales_order_details.DataSource = null; dgv_sales_order_details.Refresh(); dgv_sales_order_details.AutoGenerateColumns = false; // Set the datasource to the list where the item is added dgv_sales_order_details.DataSource = sales_order.sales_order_details; DataGridViewComboBoxColumn product_code_col = new DataGridViewComboBoxColumn(); DataGridViewColumn description_col = new DataGridViewColumn(); DataGridViewColumn quantity_col = new DataGridViewColumn(); DataGridViewColumn price_col = new DataGridViewColumn(); DataGridViewColumn account_col = new DataGridViewColumn(); DataGridViewComboBoxCell product_cell = new DataGridViewComboBoxCell(); DataGridViewTextBoxCell description_cell = new DataGridViewTextBoxCell(); DataGridViewTextBoxCell amount_cell = new DataGridViewTextBoxCell(); product_cell.DisplayMember = "name"; // They have the same Datasource as the combobox above. product_cell.DataSource = inventories; product_code_col.CellTemplate = product_cell; product_code_col.DataPropertyName = nameof(sales_order_detail.inventory.name); //This binds the value to your column product_code_col.HeaderText = "Code"; product_code_col.Name = "name"; description_col.CellTemplate = description_cell; description_col.DataPropertyName = nameof(sales_order_detail.description); description_col.HeaderText = "Description"; description_col.Name = "description"; quantity_col.CellTemplate = amount_cell; quantity_col.DataPropertyName = nameof(sales_order_detail.quantity); quantity_col.HeaderText = "Quantity"; quantity_col.Name = "quantity"; quantity_col.DefaultCellStyle.Format = "0.00"; quantity_col.DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleRight; price_col.CellTemplate = amount_cell; price_col.DataPropertyName = nameof(sales_order_detail.price); price_col.HeaderText = "Price"; price_col.Name = "price"; price_col.DefaultCellStyle.Format = "0.00"; price_col.DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleRight; dgv_sales_order_details.Columns.Add(product_code_col); dgv_sales_order_details.Columns.Add(description_col); dgv_sales_order_details.Columns.Add(quantity_col); dgv_sales_order_details.Columns.Add(price_col); dgv_sales_order_details.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill; } 

This is the result when the item is added, but since you can see that the combobox column does not display the value, it only displays the value when I click the combobox column. and when I change the value in the dropdown above the list, the value in the combobox column also changes. they seem to be attached.

My goal is to add a row to the datagrid where the comboboxcolumn displays what I have selected and fix the duplicate combo box selection.

Please comment if this requires clarification so that I can fix it. Thanks!

Answer 1

I managed to solve it, this is my decision. This is the best solution that I have come up with so far. Please comment if you have any corrections. so we could improve it. Hope this helps others too.

• Created a DataGridView handler so that I can reuse it in other forms and add additional conditions for its flexibility.

   namespace Project.Classes { public static class DGV_Handler { public static DataGridViewComboBoxColumn CreateInventoryComboBox() { DataGridViewComboBoxColumn combo = new DataGridViewComboBoxColumn(); // This lets the combo box display the data selected // I set the datasource with new instance because if i use the Datasource used in the combobox in the item selection. the combobox in the grid and that combox will be binded. if i change one combobox the other one follows. combo.DataSource = new Inventory().read_inventory(); combo.DataPropertyName = "inventory_id"; combo.DisplayMember = "name"; combo.ValueMember = "inventory_id"; combo.Name = "inventory_id"; combo.HeaderText = "Code"; combo.DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleLeft; return combo; } public static DataGridViewComboBoxColumn CreateGLAccountComboBox() { DataGridViewComboBoxColumn combo = new DataGridViewComboBoxColumn(); combo.DataSource = new Account().read(); combo.DataPropertyName = "gl_account_sales"; combo.DisplayMember = "account_name"; combo.ValueMember = "account_id"; combo.Name = "account_id"; combo.HeaderText = "Account"; combo.DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleLeft; return combo; } public static DataGridViewTextBoxColumn CreateTextBox(string dataproperty, string headertext, string name, bool is_numbers) { DataGridViewTextBoxColumn textbox = new DataGridViewTextBoxColumn(); textbox.DataPropertyName = dataproperty; textbox.HeaderText = headertext; textbox.Name = name; if (is_numbers) { textbox.DefaultCellStyle.Format = "0.00"; textbox.DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleRight; } return textbox; } } } 

• When the form is loaded, I initialize the datagrid as follows.

   private void initialize_datagrid() { dgv_sales_order_details.Columns.Clear(); dgv_sales_order_details.Refresh(); dgv_sales_order_details.AutoGenerateColumns = false; dgv_sales_order_details.DataSource = bindingSource1; dgv_sales_order_details.Columns.Add(DGV_Handler.CreateInventoryComboBox()); dgv_sales_order_details.Columns.Add(DGV_Handler.CreateTextBox("description","Description", "description", false)); dgv_sales_order_details.Columns.Add(DGV_Handler.CreateTextBox("quantity","Quantity","quantity", true)); dgv_sales_order_details.Columns.Add(DGV_Handler.CreateTextBox("price", "Price", "price", true)); dgv_sales_order_details.Columns.Add(DGV_Handler.CreateGLAccountComboBox()); dgv_sales_order_details.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill; dgv_sales_order_details.RowHeadersVisible = false; dgv_sales_order_details.EditMode = DataGridViewEditMode.EditOnEnter; } 

• Code when adding a new line

   private void btn_add_item_Click(object sender, EventArgs e) { if(validate_selection()) { // Set the properties to be included in the DGV Column var selected_row = (cb_inventory.SelectedValue as Inventory); var selected_gl_account = (cb_gl_account.SelectedValue as Account); string description = tx_description.Text; decimal quantity = tx_quantity.Value; decimal price = Convert.ToDecimal(tx_price.Text); int gl_account_id = selected_gl_account.account_id; // When something new is added to the bindingsource, the DGV will be refresh bindingSource1.Add(new Sales_Order_Detail(selected_row, description, quantity, price, 0, gl_account_id)); clear_item_selection(); } } 

Result

Answer 2

 DataGridViewComboBoxColumn c = new DataGridViewComboBoxColumn(); c.Name = "ComboColumn"; c.DataSource = dataTable; c.ValueMember = "ID"; c.DisplayMember = "Item"; dataGridView1.Columns.Add(c); 

To select a specific value, you set the Value property for this cell.

 dataGridView1.Rows[rowIndexYouWant].Cells["ComboColumn"].Value = 1; 

Please note that this type is important! IF , you say you get a System.FormatException . This may be caused by setting the wrong type to value.

When you set the value to 1, you assign int - if for some reason you have rows in the ID column, you will get a System.FormatException exception that you see.

If the types are different, you need to either update the DataTable definition or set a value for the string:

 dataGridView1.Rows[rowIndexYouWant].Cells["ComboColumn"].Value = "1"; 

to add lines you may need

 dataGridView1.Rows.Add(); int z=0; for (int a = 0; a < dataGridView1.comlumncount; a++) { dataGridView1.Rows[z].Cells[a].Value = "yourvalue"; z++; } 

For reference, check the Link , you can solve your problem.