How to use ComboBox in C#
By FoxLearn 7/16/2024 8:35:51 AM 7.91K
How to use Combobox control in C#
Open your Visual Studio, then click New Project. Select Visual C# on the left, then Windows and then select Windows Forms Application. Enter name your project, then click OK button.
Next, Open your form designer, then drag and drop a ComboBox control onto the Form from the Visual Studio toolbox.
Here's a basic example of how to create and use a ComboBox in C#
This is just a basic c# example. I'll show you how to add item or binding item to combobox, then get selected item from combobox in C#.
I'll create a State class to map data
public class States { public string ID { get; set; } public string Name { get; set; } }
Select the state combobox, then add a SelectedIndexChanged event handler.
// ComboBox C# Winform private void cboState_SelectedIndexChanged(object sender, EventArgs e) { lblValue.Text = cboState.Text; }
You can subscribe to the SelectedIndexChanged
event to handle changes in selection.
When the selection changes, the cboState_SelectedIndexChanged event handler is triggered, setting the value to label control with the selected item's text.
Double click to your form to add a Form_Load event handler that allows you to initialize data for the combobox control.
// ComboBox DataSource C# private void Form1_Load(object sender, EventArgs e) { //Add item to combobox cboState.Items.Add("Arizona"); cboState.Items.Add("Ohio"); cboState.SelectedIndex = 1; //Clear all item cboState2 cboState2.Items.Clear(); //Init data List<States> list = new List<States>(); list.Add(new States() { ID = "01", Name = "Texas" }); list.Add(new States() { ID = "02", Name = "Ohio" }); list.Add(new States() { ID = "02", Name = "Utah" }); list.Add(new States() { ID = "04", Name = "Vermont" }); //Set display member and value member for combobox cboState2.DataSource = list; cboState2.ValueMember = "ID"; cboState2.DisplayMember = "Name"; }
You can set the default selection using the SelectedIndex
property.
Select the state2 combobox, then add a SelectionChangeCommitted event handler that allows you to update text to the label control.
// C# ComboBox text change event private void cboState2_SelectionChangeCommitted(object sender, EventArgs e) { //Cast item to State object States obj = cboState2.SelectedItem as States; if (obj != null) lblValue.Text = obj.Name; }
ComboBoxes offer various properties and events for customization and interaction, such as DropDownStyle
, DropDownWidth
, DropDownHeight
, SelectedItem
, SelectedIndex
, TextChanged
, etc. You can explore these properties and events to tailor the ComboBox behavior to your application's needs.
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