Whether the task dialog can be cancelled if no cancel button is specified. 
Namespace: Autodesk.Revit.UIAssembly: RevitAPIUI (in RevitAPIUI.dll) Version: 21.0.0.0 (21.1.1.109)
Since: 2011
Syntax
| C# | 
|---|
public bool AllowCancellation { get; set; }  | 
| Visual Basic | 
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Public Property AllowCancellation As Boolean Get Set  | 
| Visual C++ | 
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public: property bool AllowCancellation { bool get (); void set (bool value); }  | 
Remarks
 The default value is true. If there is a cancel button in the task dialog, the it always can be cancelled.