# CheckList Get started with TreeView, a WinForms control to help users display a hierarchical item list. See more in documentation here. ## Content CheckList control displays a collection of items via list box embedded with multiple check boxes (small square shaped selection boxes). It enables multiple selection of items using different states of the check boxes. Additionally, the CheckList control is represented by the C1CheckList class which allows you to perform various operations on the control. ### Add and Remove CheckList Items You can access the item collection of CheckList using **Items** property of the **C1CheckList** class and add or remove the objects from the list at runtime. To add an item to the CheckList, you can use the **Add** method. ![This image shows example of CheckList control.](https://cdn.mescius.io/document-site-files/images/56bb69d1-e225-4d79-8965-f70a0e789043/images/checklist.png) The following sample code add items from the CheckList control. ```ADD // Add all items to the CheckList control lCheckList.Items.Add(c1CheckListItem1); lCheckList.Items.Add(c1CheckListItem2); lCheckList.Items.Add(c1CheckListItem3); lCheckList.Items.Add(c1CheckListItem4); lCheckList.Items.Add(c1CheckListItem5); lCheckList.Items.Add(c1CheckListItem6); lCheckList.Items.Add(c1CheckListItem7); // Assign names to each Checklist item c1CheckListItem1.Value = "Violet"; c1CheckListItem2.Value = "Indigo"; c1CheckListItem3.Value = "Blue"; c1CheckListItem4.Value = "Green"; c1CheckListItem5.Value = "Yellow"; c1CheckListItem6.Value = "Orange"; c1CheckListItem7.Value = "Red"; ``` To remove specific items from the list, you can use **Remove** method. The following sample code remove items from the CheckList control. ```REMOVE lCheckList.Items.Remove(c1CheckListItem5); lCheckList.Items.Remove(c1CheckListItem7); ``` ### Data Binding Binding a control with a data source gives you ability to communicate and even update the underlying data through the control. You can bind CheckList using any of the following ways: * Bind with database * Bind with Object Collection #### Bind with Database You can bind the CheckList to a data source by following these steps: 1. Create a connection string and fetch data from a database to a data set. ```csharp static string GetConnectionString() { //if process is 32bit use JET.OLEDB otherwise use ACE.OLEDB string provider = "Microsoft.Jet.OLEDB.4.0"; if (Environment.Is64BitProcess) provider = "Microsoft.Ace.OLEDB.12.0"; string connectionString = $"Provider={provider};Data Source=" + System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments), @"ComponentOne Samples\Common\C1NWind.mdb") + ";"; return string.Format(connectionString); } DataTable GetDataSource(string selectStatement) { // Set up connection string string conn = GetConnectionString(); // Set up SQL statement string rs = selectStatement; // Retrieve data into DataSet OleDbDataAdapter da = new OleDbDataAdapter(rs, conn); DataSet ds = new DataSet(); da.Fill(ds); // Return data table return ds.Tables[0]; } ``` 2. Set the **DataSource** and **DisplayMemberPath** properties of the CheckList control. ```csharp lCheckList.BindingInfo.DataSource = GetDataSource("Select * from Employees "); lCheckList.BindingInfo.DisplayMemberPath = "FirstName"; ``` After completing the above mentioned steps, you will get the following result. ![Bind DataSource with CheckList](https://cdn.mescius.io/document-site-files/images/56bb69d1-e225-4d79-8965-f70a0e789043/images/checklist_datasource.gif) #### Bind with Object Collection To bind the CheckList control to a list of data objects, follow these steps: 1. Create a class named Customer using the following code. ```csharp public class Customer { string name; string customerID; string mobile; string email; public Customer(string _name, string _custId, string _mobile, string _email) { this.name = _name; this.customerID = _custId; this.mobile = _mobile; this.email = _email; } public string Name { get { return name; } } public string CustomerID { get { return customerID; } } public string Mobile { get { return mobile; } } public string Email { get { return email; } } } ``` 2. Add objects of Customer class to a BindingList and set C1CheckList’s **DataSource** and **DisplayMemberPath** properties at Form\_Load event. ```csharp BindingList customers = new BindingList(); customers.Add(new Customer("John", "C001", "8888832141", "john@gmail.com")); customers.Add(new Customer("Alex", "C002", "8888832142", "@gmail.com")); customers.Add(new Customer("Shawn", "C003", "8888832143", "shawn@gmail.com")); customers.Add(new Customer("Sam", "C004", "8888832144", "sam@gmail.com")); customers.Add(new Customer("Neo", "C005", "8888832145", "neo@gmail.com")); customers.Add(new Customer("Paul", "C006", "8888832146", "paul@gmail.com")); lCheckList.BindingInfo.DataSource = customers; lCheckList.BindingInfo.DisplayMemberPath = "Name"; ``` After completing the above mentioned steps, you get the following result. ![Bind Object Collection with CheckList](https://cdn.mescius.io/document-site-files/images/56bb69d1-e225-4d79-8965-f70a0e789043/images/checklist_object.gif) ### Selection You can select/deselect all items in the list with single selection. To enable this option, you need to set the **ShowSelectAll** property to true. On setting this property to true, the Select All check box appears on top of the list of items. When you deselect the Select All check box, all items in the list are deselected. ![Set ShowSelectAll property in CheckList](https://cdn.mescius.io/document-site-files/images/56bb69d1-e225-4d79-8965-f70a0e789043/images/showselect.gif) The following sample code shows how to select/deselect all items in the list. ```csharp // To show the Select All checkbox lCheckList.ShowSelectAll = true; ``` In order to display CheckList control with the selected item at initial stage, you can use the following sample code. ![Set item in the initial stage](https://cdn.mescius.io/document-site-files/images/56bb69d1-e225-4d79-8965-f70a0e789043/images/selecteditem.png) ```csharp // Make the third item from top appear in the selected state in the CheckList control lCheckList.SelectedItem = c1CheckListItem3; ``` You can use the **SelectionMode** property to determine whether a user can select one or more than one item from the header. This property lets you choose between the following selection modes through **SelectionMode** enumeration: * **Single**: Allows you to select only one item at a time. * **Multiple**: Allows you to select multiple items without holding down a modifier key. * **Radio**: Allows you to select only one item at a time and deselect the item while holding down the ctrl modifier key. * **Extended**: Allows you to select multiple consecutive items while holding down the corresponding modifier key. ![Select multiple values in CheckList](https://cdn.mescius.io/document-site-files/images/56bb69d1-e225-4d79-8965-f70a0e789043/images/multiple_values.gif) The following sample code shows the method to set the SelectionMode property. ```csharp // To select multiple items at the same time lCheckList.SelectionMode = C1.Win.TreeView.SelectionMode.Multiple; ``` ### Show or Hide CheckBoxes You can set the visibility of check boxes in the CheckList control by using **ShowCheckBoxes** property of the **C1CheckList** class. The following image displays CheckList items without the check boxes. ![Hide checkboxes in CheckList](https://cdn.mescius.io/document-site-files/images/56bb69d1-e225-4d79-8965-f70a0e789043/images/hide_checkboxes.png) The following sample code sets the visibility of checkbox in the CheckList control. ```csharp // Hide checkboxes for each CheckList item lCheckList.ShowCheckBoxes = false; ``` ### Customize Captions You can customize the CheckList control as per your requirements. You can change the captions of Select All option using **SelectAllCaption** property and the caption of Unselect All option using **UnselectAllCaption** property of the C1CheckList class. ![Set captions for Select All/ Unselect All option](https://cdn.mescius.io/document-site-files/images/56bb69d1-e225-4d79-8965-f70a0e789043/images/checklist_caption.gif) The following sample code sets the SelectAllCaption and UnselectAllCaption property of CheckList. ```csharp lCheckList.ShowCheckBoxes = true; lCheckList.SelectAllCaption = "Colors Check All"; lCheckList.UnselectAllCaption = "Colors UnCheck All"; ``` ### Appearance and Style CheckList allows you to change the appearance and style of all items in the control. You can use the **BorderColor** and **BorderStyle** property to style the border of the CheckList. In addition, you can also set the style of default, selected and hot state of CheckList control. The following GIF shows the style applied to the CheckList's items. ![Change style of CheckList](https://cdn.mescius.io/document-site-files/images/56bb69d1-e225-4d79-8965-f70a0e789043/images/style_colors.gif) ```csharp // Set the color of checkbox lCheckList.Styles.CheckBoxColor = Color.Brown; // Set the border style lCheckList.BorderStyle = BorderStyle.Fixed3D; lCheckList.BorderColor = Color.Black; // Gets style for the default state of CheckList lCheckList.Styles.Default.BackColor = Color.OldLace; lCheckList.Styles.Default.ForeColor = Color.Maroon; // Gets style for the selected state of CheckList lCheckList.Styles.Selected.BackColor = Color.LightYellow; lCheckList.Styles.Selected.ForeColor = Color.DeepPink; // Gets style for the hot state of CheckList lCheckList.Styles.Hot.BackColor = Color.Orange; lCheckList.Styles.Hot.ForeColor = Color.LightGray; ```