You cannot removed all the elements from current solution. At least there should be two elements in the solution.

Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0)

Syntax

C#
`public static FailureDefinitionId NotAllowedToRemoveAllElements { get; }`

Visual Basic
`Public Shared ReadOnly Property NotAllowedToRemoveAllElements As FailureDefinitionId Get`

Visual C++
`public: static property FailureDefinitionId^ NotAllowedToRemoveAllElements { FailureDefinitionId^ get (); }`

See Also