--- title: "Drag-and-drop mouse behaviors" description: Learn about how drag-and-drop works on Windows Forms, including how to perform drag-and-drop with the mouse. ms.date: 10/26/2020 ms.topic: conceptual dev_langs: - "csharp" - "vb" helpviewer_keywords: - "drag and drop [Windows Forms], Windows Forms" - "Windows Forms, drag and drop" --- # Drag-and-drop mouse behavior overview (Windows Forms .NET) Windows Forms includes a set of methods, events, and classes that implement drag-and-drop behavior. This topic provides an overview of the drag-and-drop support in Windows Forms. [!INCLUDE [desktop guide under construction](../../includes/desktop-guide-preview-note.md)] ## Drag-and-drop events There are two categories of events in a drag and drop operation: events that occur on the current target of the drag-and-drop operation, and events that occur on the source of the drag and drop operation. To perform drag-and-drop operations, you must handle these events. By working with the information available in the event arguments of these events, you can easily facilitate drag-and-drop operations. ## Events on the current drop target The following table shows the events that occur on the current target of a drag-and-drop operation. | Mouse Event | Description | |-----------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | | This event occurs when an object is dragged into the control's bounds. The handler for this event receives an argument of type . | | | This event occurs when an object is dragged while the mouse pointer is within the control's bounds. The handler for this event receives an argument of type . | | | This event occurs when a drag-and-drop operation is completed. The handler for this event receives an argument of type . | | | This event occurs when an object is dragged out of the control's bounds. The handler for this event receives an argument of type . | The class provides the location of the mouse pointer, the current state of the mouse buttons and modifier keys of the keyboard, the data being dragged, and values that specify the operations allowed by the source of the drag event and the target drop effect for the operation. ## Events on the drop source The following table shows the events that occur on the source of the drag-and-drop operation. |Mouse Event|Description| |-----------------|-----------------| ||This event occurs during a drag operation. It provides an opportunity to give a visual cue to the user that the drag-and-drop operation is occurring, such as changing the mouse pointer. The handler for this event receives an argument of type .| ||This event is raised during a drag-and-drop operation and enables the drag source to determine whether the drag-and-drop operation should be canceled. The handler for this event receives an argument of type .| The class provides the current state of the mouse buttons and modifier keys of the keyboard, a value specifying whether the ESC key was pressed, and a value that can be set to specify whether the drag-and-drop operation should continue. ## Performing drag-and-drop Drag-and-drop operations always involve two components, the **drag source** and the **drop target**. To start a drag-and-drop operation, designate a control as the source and handle the event. In the event handler, call the method providing the data associated with the drop and the a value. Set the target control's property set to `true` to allow that control to accept a drag-and-drop operation. The target handles two events, first an event in response to the drag being over the control, such as . And a second event which is the drop action itself, . The following example demonstrates a drag from a control to a . When the drag is completed, the `TextBox` responds by assigning the label's text to itself. ```csharp // Initiate the drag private void label1_MouseDown(object sender, MouseEventArgs e) => DoDragDrop(((Label)sender).Text, DragDropEffects.All); // Set the effect filter and allow the drop on this control private void textBox1_DragOver(object sender, DragEventArgs e) => e.Effect = DragDropEffects.All; // React to the drop on this control private void textBox1_DragDrop(object sender, DragEventArgs e) => textBox1.Text = (string)e.Data.GetData(typeof(string)); ``` ```vb ' Initiate the drag Private Sub Label1_MouseDown(sender As Object, e As MouseEventArgs) DoDragDrop(DirectCast(sender, Label).Text, DragDropEffects.All) End Sub ' Set the effect filter and allow the drop on this control Private Sub TextBox1_DragOver(sender As Object, e As DragEventArgs) e.Effect = DragDropEffects.All End Sub ' React to the drop on this control Private Sub TextBox1_DragDrop(sender As Object, e As DragEventArgs) TextBox1.Text = e.Data.GetData(GetType(String)) End Sub ``` For more information about the drag effects, see and . ## See also - [Overview of using the mouse (Windows Forms .NET)](overview.md) - - - -