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Removed OnXXX methods in favor of events, fixed bug in Drop, added example in docs

pull/38/head
David Hall 2019-01-31 11:38:37 -07:00
parent 7dcab68cd3
commit 15b3a02b86
1 changed files with 98 additions and 35 deletions
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133
Windows.Shell/ShellDropTarget.cs
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@ -13,12 +13,95 @@ namespace Vanara.Windows.Shell
/// their equivalent On[MethodName] equivalents. To specialize their handling, simply override the On[MethodName] method or hook an event
/// to the corresponding event.
/// </summary>
/// <remarks>
/// This class provides an easy means of creating a COM based out-of-process DropTarget.
/// <list type="number">
/// <item>Create a .NET application project.</item>
/// <item>Delete the Program.cs file that includes the Main method.</item>
/// <item>Create a new class and derive it from <see cref="ShellDropTarget"/> with the attributes in the example below.</item>
/// </list>
/// <para><b>Example:</b></para>
/// <code title="Example">[Guid("&lt;Your GUID here&gt;"), ClassInterface(ClassInterfaceType.None)]
///public class MyDropTarget : ShellDropTarget
///{
/// // In your constructor, be sure to override the DragEnter and DragDrop events and set the effect you desire.
/// public MyDropTarget() : base()
/// {
/// // Setting the effect to Copy here ensure we continue to get drag/drop messages
/// DragEnter += (s, e) =&gt; e.Effect = DragDropEffects.Copy;
///
/// DragDrop += MyDragDrop;
/// }
///
/// // This event handler for DragDrop should never hold up the shell. To accommodate a non-blocking response,
/// // use the 'QueueNonBlockingCallback' method which uses PostThreadMessage to run a delegate as shown below.
/// private void MyDragDrop(object sender, DragEventArgs e)
/// {
/// // Setting the effect to None here ends drag/drop messages
/// e.Effect = DragDropEffects.None;
/// // Notice we're passing in the DragEventArgs.Data property that contains the shell item array from the Shell.
/// QueueNonBlockingCallback(DisplayData, e.Data);
/// }
///
/// // This delegate will get run outside of the Shell's calling path and can display a UI or perform any other
/// // function on the list of shell items passed to it.
/// private void DisplayData(object ido)
/// {
/// // *** Replace with your functionality ***
/// using (var shia = ShellItemArray.FromDataObject(ido as DataObject))
/// {
/// var szMsg = $"Found {shia.Count} item(s): " + string.Join(", ", shia.Select(i =&gt; i.Name));
/// MessageBox.Show(szMsg, "MyDropTarget");
/// }
/// // Don't fail to call QuitMessageLoop once you're done processing the Shell call.
/// QuitMessageLoop();
/// }
///
/// // This is the main thread of the application. When called from the Shell, it will append the -embedding argument to indicate that
/// // a message loop needs to start running and the COM server registered. All that is accomplished by calling the 'Run' method
/// // on your new class.
/// [STAThread]
/// private static void Main(string[] args)
/// {
/// // *** Replace with your ProgID, name and display name ***
/// const string progID = "txtfile";
/// const string verbDisplayName = "DropTarget Verb Sample";
/// const string verbName = "DropTargetVerb";
///
/// var arg = args.Length &gt; 0 ? args[0].TrimStart('-', '/').ToLowerInvariant() : null;
/// switch (arg)
/// {
/// // Handle a call from the Shell launching this out-of-proc server
/// case "embedding":
/// new MyDropTarget().Run(TimeSpan.FromSeconds(30));
/// break;
///
/// // Unregister this out-of-proc server from handling the DropTarget. This can be ommitted if done by an installer.
/// case "unregister":
/// using (var progid = new ProgId(progID, false))
/// progid.Verbs.Remove(verbName);
/// ShellRegistrar.UnregisterLocalServer&lt;MyDropTarget&gt;(false);
/// break;
///
/// // Register this out-of-proc server to handle the DropTarget. This can be ommitted if done by an installer.
/// default:
/// ShellRegistrar.RegisterLocalServer&lt;MyDropTarget&gt;("MyTestDropTarget", systemWide: false);
/// using (var progid = new ProgId(progID, false))
/// using (var verb = progid.Verbs.Add(verbName, verbDisplayName))
/// {
/// verb.DropTarget = Marshal.GenerateGuidForType(typeof(MyDropTarget));
/// verb.NeverDefault = true;
/// }
/// break;
/// }
/// }
///}</code></remarks>
/// <seealso cref="Vanara.Windows.Shell.ComObject"/>
/// <seealso cref="Vanara.PInvoke.Ole32.IDropTarget"/>
public abstract class ShellDropTarget : ComObject, IDropTarget
{
private DataObject lastDataObject;
private DROPEFFECT lastEffect;
private DROPEFFECT lastEffect = DROPEFFECT.DROPEFFECT_NONE;
/// <summary>Initializes a new instance of the <see cref="ShellDropTarget"/> class.</summary>
protected ShellDropTarget() : base() { }
@ -31,9 +114,6 @@ namespace Vanara.Windows.Shell
/// <summary>Occurs when a drag-and-drop operation is started. All calls from this event must be non-blocking.</summary>
public event DragEventHandler DragDrop;
/// <summary>Occurs when a drag-and-drop operation is completed.</summary>
public event DragEventHandler DragDropComplete;
/// <summary>Occurs to request whether a drop can be accepted, and, if so, the effect of the drop.</summary>
public event DragEventHandler DragEnter;
@ -49,16 +129,18 @@ namespace Vanara.Windows.Shell
/// <inheritdoc/>
HRESULT IDropTarget.DragEnter(IDataObject pDataObj, uint grfKeyState, Point pt, ref DROPEFFECT pdwEffect)
{
var arg = CreateDragEventArgs(pDataObj, grfKeyState, pt, pdwEffect);
OnDragEnter(arg);
lastEffect = pdwEffect = (DROPEFFECT)arg.Effect;
System.Diagnostics.Debug.WriteLine($"IDropTarget.DragEnter: effect={pdwEffect}");
var drgevent = CreateDragEventArgs(pDataObj, grfKeyState, pt, pdwEffect);
DragEnter?.Invoke(this, drgevent);
lastEffect = pdwEffect = (DROPEFFECT)drgevent.Effect;
return HRESULT.S_OK;
}
/// <inheritdoc/>
HRESULT IDropTarget.DragLeave()
{
OnDragLeave(EventArgs.Empty);
System.Diagnostics.Debug.WriteLine("IDropTarget.DragLeave");
DragLeave?.Invoke(this, EventArgs.Empty);
lastDataObject = null;
return HRESULT.S_OK;
}
@ -66,42 +148,23 @@ namespace Vanara.Windows.Shell
/// <inheritdoc/>
HRESULT IDropTarget.DragOver(uint grfKeyState, Point pt, ref DROPEFFECT pdwEffect)
{
var arg = CreateDragEventArgs(null, grfKeyState, pt, pdwEffect);
OnDragOver(arg);
lastEffect = pdwEffect = (DROPEFFECT)arg.Effect;
System.Diagnostics.Debug.WriteLine($"IDropTarget.DragOver: effect={pdwEffect}");
var drgevent = CreateDragEventArgs(null, grfKeyState, pt, pdwEffect);
DragOver?.Invoke(this, drgevent);
lastEffect = pdwEffect = (DROPEFFECT)drgevent.Effect;
return HRESULT.S_OK;
}
/// <inheritdoc/>
HRESULT IDropTarget.Drop(IDataObject pDataObj, uint grfKeyState, Point pt, ref DROPEFFECT pdwEffect)
{
var arg = CreateDragEventArgs(pDataObj, grfKeyState, pt, pdwEffect);
OnDragDrop(arg);
lastEffect = pdwEffect = (DROPEFFECT)arg.Effect;
QueueNonBlockingCallback(o => OnDragDropComplete((DragEventArgs)o), arg);
System.Diagnostics.Debug.WriteLine($"IDropTarget.Drop: effect={pdwEffect}");
var drgevent = CreateDragEventArgs(pDataObj, grfKeyState, pt, pdwEffect);
DragDrop?.Invoke(this, drgevent);
pdwEffect = (DROPEFFECT)drgevent.Effect;
return HRESULT.S_OK;
}
/// <summary>Raises the <see cref="E:DragDrop"/> event.</summary>
/// <param name="drgevent">The <see cref="DragEventArgs"/> instance containing the event data.</param>
protected virtual void OnDragDrop(DragEventArgs drgevent) => DragDrop?.Invoke(this, drgevent);
/// <summary>Raises the <see cref="E:DragDropComplete"/> event.</summary>
/// <param name="drgevent">The <see cref="DragEventArgs"/> instance containing the event data.</param>
protected virtual void OnDragDropComplete(DragEventArgs drgevent) => DragDropComplete?.Invoke(this, drgevent);
/// <summary>Raises the <see cref="E:DragEnter"/> event.</summary>
/// <param name="drgevent">The <see cref="DragEventArgs"/> instance containing the event data.</param>
protected virtual void OnDragEnter(DragEventArgs drgevent) => DragEnter?.Invoke(this, drgevent);
/// <summary>Raises the <see cref="E:DragLeave"/> event.</summary>
/// <param name="ev">The <see cref="EventArgs"/> instance containing the event data.</param>
protected virtual void OnDragLeave(EventArgs ev) => DragLeave?.Invoke(this, ev);
/// <summary>Raises the <see cref="E:DragOver"/> event.</summary>
/// <param name="drgevent">The <see cref="DragEventArgs"/> instance containing the event data.</param>
protected virtual void OnDragOver(DragEventArgs drgevent) => DragOver?.Invoke(this, drgevent);
private DragEventArgs CreateDragEventArgs(IDataObject pDataObj, uint grfKeyState, Point pt, DROPEFFECT pdwEffect)
{
var data = pDataObj == null ? lastDataObject : new DataObject(pDataObj);