Drop down list box control in c#

Only one list item is displayed at one time in a ComboBox and other available items are loaded in a drop down list. Only one list item is displayed at one time in a ComboBox and rest of the available items are loaded in a drop down list. Creating a ComboBox control at run-time includes creating an instance of ComboBox class, set its properties and add ComboBox instance to the Form controls.

First step to create a dynamic ComboBox is to create an instance of ComboBox class. The following code snippet creates a ComboBox control object.

The following code snippet sets location, width, height, background color, foreground color, Text, Name, and Font properties of a ComboBox. To do so, we use Form. Add method. The following code snippet adds a ComboBox control to the current Form.

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The easiest way to set properties is from the Properties Window. You can open Properties window by pressing F4 or right click on a control and select Properties menu item.

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The Properties window looks like Figure 2. It is used to access control in the code. The following code snippet sets and gets the name and text of a ComboBox control. When you click on the Collections, the String Collection Editor window will pop up where you can type strings.

Each line added to this collection will become a ComboBox item. I add four items as you can see from Figure 6. View All. Mahesh Chand Updated date Mar 07, The ComboBox control provides combined functionality of a text box and a listbox in a single control. Once a ComboBox is on the Form, you can move it around and resize it and set its properties and events using the Properties and Events windows.

Once the ComboBox control is ready with its properties, the next step is to add the ComboBox to a Form. Setting ComboBox Properties Alternatively, you can set control properites at design time. The Location property is a type of Point that specifies the starting position of the ComboBox on a Form.

You may also use Left and Top properties to specify the location of a control from the left top corner of the Form. The Size property specifies the size of the control. We can also use Width and Height property instead of Size property. The DropDownHeight and DropDownWidth properties represent the height and width of the dropdown area in pixel respectively. If all the items do not fit in the size of the dropdown area, the scrollbars will appear as you can see from Figure 3.

Font property represents font of text of a ComboBox control.The ListBox control enables you to display a list of items to the user that the user can select by clicking. You can set ListBox properties by using Properties Window.

In order to get Properties window you can Press F4 or by right-clicking on a control to get the "Properties" menu item. You can set property values in the right side column of the property window. In addition to display and selection functionality, the ListBox also provides features that enable you to efficiently add items to the ListBox and to find text within the items of the list. You can use the Add or Insert method to add items to a list box. The Add method adds new items at the end of an unsorted list box.

If the Sorted property of the C ListBox is set to true, the item is inserted into the list alphabetically. Otherwise, the item is inserted at the end of the ListBox. You can inserts an item into the list box at the specified index. If you want to retrieve a single selected item to a variableuse the following code. The SelectionMode property determines how many items in the list can be selected at a time. A ListBox control can provide single or multiple selections using the SelectionMode property.

drop down list box control in c#

If you change the selection mode property to multiple selectthen you will retrieve a collection of items from ListBox1. SelectedItems property. The ListBox class has two SelectionMode. Multiple or Extended. In Multiple modeyou can select or deselect any item in a ListBox by clicking it.

In Extended mode, you need to hold down the Ctrl key to select additional items or the Shift key to select a range of items. The following C program initially fill seven days in a week while in the form load event and set the selection mode property to MultiSimple. At the Button click event it will display the selected items. The Items collection of C Winforms Listbox returns a Collection type of Object so you can use ToString on each item to display its text value as below:.

The next step is to bind this List to the Listbox. In order to do that you should set datasource of the Listbox. First of all, you could create a connection string and fetch data from database to a Dataset. Next step is that you have set Listbox datasoure as Dataset. When you want to clear the Listbox, if the ListBox already binded with Datasourceyou have to set the Datasource of Listbox as null.

This event is fired when the item selection is changed in a ListBox.Join Stack Overflow to learn, share knowledge, and build your career. Connect and share knowledge within a single location that is structured and easy to search. Or is it possible to configure a combobox so that the user can't add values but rather only select from the available list of values?

Specifies that the list is displayed by clicking the down arrow and that the text portion is not editable. This means that the user cannot enter a new value. Only values already in the list can be selected. Set the ComboBox. Learn more. C how can I make a listbox dropdown like a combobox does?

Ask Question. Asked 10 years, 9 months ago. Active 4 years, 1 month ago. Viewed 22k times. How can I make a listbox dropdown like a combobox? This is for a desktop application. Junaith 3, 20 20 silver badges 30 30 bronze badges. Also, by default, a user will only be able to select items from a ComboBox.

Thanks for the clarification. It would have helped in the post had been tagged "winforms".

ASP.NET Multiple Selection DropDownList Using .NET C#

Show 3 more comments. Active Oldest Votes. Set it to DropDownList. Mashmagar Mashmagar 2, 2 2 gold badges 27 27 silver badges 37 37 bronze badges. Add a comment. Set the DropDownStyle to DropDownList : Specifies that the list is displayed by clicking the down arrow and that the text portion is not editable.

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Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown.These four controls inherits from the same base class, called ListControl. Since they inherit from the same class, these four controls share many properties and methods, such as Clearwhich will clear all existing items in the list, or SelectedItem, which will return the selected list item.

When you select the control you will see a small arrow button on the top-right of the control. When you click on that arrow button, you will see the following small menu:. Please also note that if you want to enable AutoPostBack for a list control, you can do so using this small menu. Go ahead and add two items as seen in the following figure.

The text and value properties of each list item will carry the same value. After you are done, please click OK button. We could also add the items using the html markup.

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Manually adding items to a list control is easy. However, if you are building a database-enabled project, a project that is bigger in its scope you will rarely do manual-item adding. Instead, you will populate the list controls with data coming from the database.

If this store begins to sell Electronics later, you will not add this new category manually. Instead, there will be a database where Categories are stored in a table, and the new category will be inserted to that table. Later, you will need to bind this Category table to the dropdownlist which will automatically show the new category added. All of them exactly do the same thing with slightly different approaches. You can choose the way that you feel more comfortable with.

I always prefer the third option. Please see the following snippet for the details:. Please run your application and check the html source code of the page.

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You will see that the ListBox control is rendered as select option in html. In the following code snippet, we have a string array, called categories, with three items.

C# ListBox Control

When we have a group variable, like Array or Lists, actually, we can take advantage of BindData method:. First, we need to indicate the DataSource which is categories array, then we need to call DataBind method to bind the categories to the list box.

DataBind can be used with arrays, and other collection types such as Lists. We have done exactly the same thing, except that we defined a List with string type. Click here if you want to learn more about it. You will always want to associate a unique property to DataValueField because this is the property that will help you perform further operations on a specific student.

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For example, if you want to remove a student record from the database, you will need the ID of that student not its name since there might be many students with the same name.

First, we need to add a button and a label just under the list box:. Your final code should like this:. You may think that this code will run just fine, however it will not. It is easy to print the selected item when only one item can be selected. Only in List Box, we can enable or disable multiple selection mode.

We use the SelectionMode property for this purpose as seen in the following figure:. Now, we need to print the multiple items in the label. Here is the updated version of ReturnSelectedItemsText method:.ListBox in C is defined as adding a list of elements to the ListBox to operate on single or multiple elements. Difference between the drop-down box and list box is drop-down box can select only one element at a time but in case of the list box, we can select single or multiple elements at a time.

The ListBox is used to provide different types of methods, properties, and events. This ListBox is specified under System. Forms package namespace. Step 2: Left side of the visual studio or From View choose Toolbox, Next drag and drop then the required elements onto the Form1. Step 3: After drag and drop select the properties from the right side of the Visual studio and give some name to the Text property.

This is used to write a code in the 2 nd method Run-Time. This is not directly doing it as per the above method. We have written some programs to create ListBox. If you double click on any of the dropped elements we got some C code that element action methods, we have to write our logic to what we want to do with those elements.

Steps to create Run-Time project code to create ListBox. Size, Color to elements, etc. Add "A" ; listBox. Add "B" ; listBox. Add "C" ; listBox. Add "D". Generic; using System. ComponentModel; using System. Data; using System. Drawing; using System. Linq; using System.

Text; using System. Red; listBox2. Add "Java" ; listBox2.A Visual Studio Web site project with source code is available to accompany this topic: Download.

The following code example demonstrates how to create a DropDownList control that contains four items. The following code example demonstrates how to create a DropDownList control though data binding. Use the DropDownList control to create a single-selection drop-down list control. To specify the items that you want to appear in the DropDownList control, place a ListItem object for each entry between the opening and closing tags of the DropDownList control.

The DropDownList control also supports data binding. To bind the control to a data source, create a data source, such as a System. ArrayList object, that contains the items to display in the control.

drop down list box control in c#

Then, use the Control. DataBind method to bind the data source to the DropDownList control. Use the SelectedIndex property to programmatically determine the index of the item selected by the user from the DropDownList control. The index can then be used to retrieve the selected item from the Items collection of the control.

For information about how to configure this control so that it generates markup that conforms to accessibility standards, see Accessibility in Visual Studio and ASP. NET Controls and Accessibility. Initializes a new instance of the DropDownList class. Gets or sets the application-relative virtual directory of the Page or UserControl object that contains this control. Gets the collection of arbitrary attributes for rendering only that do not correspond to properties on the control.

Gets or sets a value indicating whether a postback to the server automatically occurs when the user changes the list selection. Gets or sets a value indicating whether validation is performed when a control that is derived from the ListControl class is clicked.

Gets or sets the algorithm that is used to generate the value of the ClientID property. Gets a character value representing the separator character used in the ClientID property. Gets the HttpContext object associated with the server control for the current Web request. Gets a ControlCollection object that represents the child controls for a specified server control in the UI hierarchy. Gets a value indicating whether a Style object has been created for the ControlStyle property.

This property is primarily used by control developers. Gets a reference to the naming container if the naming container implements IDataItemContainer. Gets a reference to the naming container if the naming container implements IDataKeysControl. Gets or sets the specific table in the DataSource to bind to the control.Introduction This article is based on queries in the newsgroup:.

Query 1 :"In my application i am using dropdownlist to display all categories from a table. When the user clicks this control I display all records in that category. Category table also contains column called color. I wanted display some categories in dropdown list different color and others in different color using ASP. Note : The dropDownList has a bug which prevent us from assigning the style property to each item in the DropDownList. So as stated by the MS Article the alternative method to achieve this is by using the tag given below:.

drop down list box control in c#

To solve this the concept remains same only thing we need to do is use the ListBox and navigate through each and every record in dataset to have item with appropriate color. So lets consider the Products Table in Northwind Database and expect the output as below:.

Tag that we use:. As we have done the coding for assigning style property to each item we might as well complete the code to develop a Color Picker in ASP. NET as below:. We'll use the namespace System. The other way this can be done is by using Namespace System. ComponentModel and TypeDescripter Class. View All. Sushila Patel Updated date Mar 25, Introduction This article is based on queries in the newsgroup: Query 1 :"In my application i am using dropdownlist to display all categories from a table.

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