Control class/Start Drag method

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VI Server Method Information
Method ID 6331C0E
Scope Basic Development Environment
Data Name Start Drag
Short Name* Start Drag
Long Name* Start Drag
* Displayed here in English. Short and Long names appear in the language of the LabVIEW IDE.
Owning Class ID 6
Owning Class Name Control Class
Return Data Type No return value
Invoke Node Start Drag
Available in Real-Time Operating SystemNo
Available in Run-Time EngineYes (Read/Write)
Loads the block diagram into memoryNo
Loads the front panel into memoryNo
Need to authenticate before useNo
Remote access allowedYes
Settable when the VI is runningYes

Starts a drag and drop operation using the specified control as the source.

You can use this method to start drag and drop operations in response to user-defined actions instead of the built-in behavior with string, tree, listbox, and multicolumn listbox controls. For controls other than the string, tree, listbox, and multicolumn listbox, the Start Drag method is the only way to start a drag using this control as a drag source.

You must specify what data to provide during the drag and drop operation. Optionally, you can specify the drag mode, and corresponding default cursor feedback, to reflect whether this drag and drop operation supports moving the data instead of only copying it. During a drag and drop operation, only drag and drop events are available. Mouse events are not available.

If there is already a drag in progress, LabVIEW returns an error. If you pass an empty array for the data parameter, the drag operation does not start and LabVIEW returns an error. If the array of data passed contains duplicate data names or data that conflicts with built-in types, LabVIEW returns an error.

After you use this method, LabVIEW remains in the middle of a drag and drop operation until the user cancels the drag by pressing the <Esc> key or lifting the mouse button, or until a window opens in front of the window that has the source control.

The Drag Data parameter is an array of clusters, each cluster containing a label and corresponding data. Each label must be unique and cannot use the LV_ prefix. Each element of the array must be of the same data type. The Drag Mode parameter specifies the operation of the drag, such as copy, move, or copy and move. If you select copy or move, pressing the <Ctrl> key copies the item.


Data type Name Required Description
Common Cluster Array Drag Data Yes Indicates the LabVIEW or user-defined name that identifies the data type.
Enum U32 Drag Mode No Specifies the operations that this control supports during the drag, such as copy or move, copy only, move only. If you select copy or move, pressing the <Ctrl> key copies the item. The operations you support control the values that the Results output of the Drag Ended and Drag Source Update events can provide.

For filter events, you can modify this field to change the drag mode when this event is generated.



Version Change(s)
LabVIEW 2018 More info to come.

See Also

External Links