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FirstElement Method

Returns the first element to pass the filter(s).

Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0)
Since: 2011

Syntax

C# 
public Element FirstElement()
Visual Basic 
Public Function FirstElement As Element
Visual C++ 
public:
Element^ FirstElement()

Return Value

The first element.

Remarks

This will reset the collector to the beginning and find the first element that passes the applied filter(s). If you have an active iterator to this same collector it will be stopped by this call.

Examples

Copy C# 
public FamilyInstance GetAColumn(Autodesk.Revit.DB.Document document)
{
    // Create a filter to find all columns
    StructuralInstanceUsageFilter columnFilter = 
        new StructuralInstanceUsageFilter(StructuralInstanceUsage.Column);

    // Apply the filter to the elements in the active document
    FilteredElementCollector collector = new FilteredElementCollector(document);
    collector.WherePasses(columnFilter);

    // Get the first column from the filtered results
    // Element will be a FamilyInstance
    FamilyInstance column = collector.FirstElement() as FamilyInstance;

    return column;
}
Copy VB.NET 
Public Function GetAColumn(document As Autodesk.Revit.DB.Document) As FamilyInstance
    ' Create a filter to find all columns
    Dim columnFilter As New StructuralInstanceUsageFilter(StructuralInstanceUsage.Column)

    ' Apply the filter to the elements in the active document
    Dim collector As New FilteredElementCollector(document)
    collector.WherePasses(columnFilter)

    ' Get the first column from the filtered results
    ' Element will be a FamilyInstance
    Dim column As FamilyInstance = TryCast(collector.FirstElement(), FamilyInstance)

    Return column
End Function

Exceptions

Exception Condition
Autodesk.Revit.Exceptions InvalidOperationException The collector does not have a filter applied. Extraction or iteration of elements is not permitted without a filter.

See Also