ArcObjects SDK开发 014 MapSurround和普通Element

1、如何获取MapSurround

和获取MapFrame类似，如果你已经获取指北针、比例尺等对象，可以通过IGraphicsContainer的FindFrame函数获取。如果没有，则通过IGraphicsContainer循环所有Element去判断即可。

2、添加MapSurround

指北针、比例尺、图例等都是MapSurround，我们以最简单的指北针为例，把MapSurround添加到PageLayout上。

var myGraphicsContainer = pLayoutApplication.PageLayout as IGraphicsContainer;

var myActiveView = pLayoutApplication.PageLayout as IActiveView;

var myMap = myActiveView.FocusMap;

var myMapFrame = myGraphicsContainer.FindFrame(myMap) as IMapFrame;

if (this._MapSurroundFrame == null)

{

    this._MapSurroundFrame = new MapSurroundFrameClass();

    var myMarkerNorthArrow = new MarkerNorthArrowClass();

    var myMarkerSymbol = myMarkerNorthArrow.MarkerSymbol;

    var myCharacterMarkerSymbol = myMarkerSymbol as ICharacterMarkerSymbol;

    myCharacterMarkerSymbol.CharacterIndex = 177;

    myMarkerNorthArrow.MarkerSymbol = myCharacterMarkerSymbol;

    myMarkerNorthArrow.Size = 30;

    this._MapSurroundFrame.MapSurround = myMarkerNorthArrow;

    this._MapSurroundFrame.MapFrame = myMapFrame;

    var myQuerySize = this._MapSurroundFrame.MapSurround as IQuerySize;

    double myWidth = 0;

    double myHeight = 0;

    myQuerySize.QuerySize(ref myWidth, ref myHeight);

    var myUnitConverter = new UnitConverterClass();

    this.Width = Math.Round(myUnitConverter.ConvertUnits(myWidth, esriUnits.esriPoints, esriUnits.esriMillimeters), 1);

    this.Height = Math.Round(myUnitConverter.ConvertUnits(myHeight, esriUnits.esriPoints, esriUnits.esriMillimeters), 1);

}

else

{

    this._MapSurroundFrame.MapFrame = myMapFrame;

}

var myNewEnvelope = new EnvelopeClass

{

    XMin = this.X,

    YMin = this.Y,

    Width = this.Width,

    Height = this.Height

};

this.GetElment().Geometry = myNewEnvelope;

if (GraphicsContainerHelper.Contain(myGraphicsContainer, this.GetElment()) == false)

{

    myGraphicsContainer.AddElement(this.GetElment(), 0);

}

添加MapSurround流程都是一样的，不同的地方主要是在实例化具体MapSurround的代码。例如指北针、比例尺、图例等。实例化比例尺的代码如下。

IGraphicsContainer myGraphicsContainer = pLayoutApplication.PageLayout as IGraphicsContainer;

if (this._MapSurroundFrame != null)

{

    myGraphicsContainer.DeleteElement(this._MapSurroundFrame as IElement);

    this._MapSurroundFrame = null;

}

IActiveView myActiveView = pLayoutApplication.PageLayout as IActiveView;

IMap myMap = myActiveView.FocusMap;

IMapFrame myMapFrame = myGraphicsContainer.FindFrame(myMap) as IMapFrame;

this._MapSurroundFrame = new MapSurroundFrameClass();

this._MapSurroundFrame.MapFrame = myMapFrame;

//创建比例尺

this._ScaleBar = this.CreateScaleBar();

this._ScaleBar.Map = myMapFrame.Map;

this._ScaleBar.ResizeHint = esriScaleBarResizeHint.esriScaleBarFixed;

this._ScaleBar.LabelFrequency = esriScaleBarFrequency.esriScaleBarDivisions;

this._MapSurroundFrame.MapSurround = this._ScaleBar;

this._ScaleBar.BarHeight = this.BarHeight;

this._ScaleBar.Division = this.Division;

this._ScaleBar.Divisions = this.Divisions;

this._ScaleBar.Subdivisions = this.Subdivisions;

this._ScaleBar.DivisionsBeforeZero = this.DivisionsBeforeZero;

this._ScaleBar.LabelPosition = this.LabelPosition;

this._ScaleBar.LabelGap = this.LabelGap;

ITextSymbol myLabelSymbol = new TextSymbolClass();

IFontDisp myFontDisp = myLabelSymbol.Font;

myFontDisp.Name = "Times New Roman";

myLabelSymbol.Font = myFontDisp;

myLabelSymbol.Size = this.LabelSize;

this._ScaleBar.LabelSymbol = myLabelSymbol;

//pScaleBar的UnitLabel属性设置需要放在pScaleBar.Units设置代码之后。这样UnitLabel设置才有效果。

this._ScaleBar.Units = esriUnits.esriKilometers;

this._ScaleBar.UnitLabel = this.UnitLabel;

this._ScaleBar.UnitLabelGap = this.UnitLabelGap;

ITextSymbol myUnitLabelSymbol = new TextSymbolClass();

myFontDisp = myUnitLabelSymbol.Font;

myFontDisp.Name = "Times New Roman";

myUnitLabelSymbol.Font = myFontDisp;

myUnitLabelSymbol.Size = this.UnitLabelFontSize;

this._ScaleBar.UnitLabelSymbol = myUnitLabelSymbol;

this._ScaleBar.UnitLabelPosition = this.UnitLabelPosition;

IScaleMarks myScaleMarks = this._ScaleBar as IScaleMarks;

myScaleMarks.MarkFrequency = esriScaleBarFrequency.esriScaleBarDivisionsAndSubdivisions;

myScaleMarks.MarkPosition = this.MarkPosition;

myScaleMarks.DivisionMarkHeight = this.DivisionMarkHeight;

ILineSymbol myDivisionMarkSymbol = new SimpleLineSymbolClass();

myDivisionMarkSymbol.Color = new RgbColorClass() { Red = 0, Green = 0, Blue = 0 };

myDivisionMarkSymbol.Width = this.DivisionMarkWidth;

myScaleMarks.DivisionMarkSymbol = myDivisionMarkSymbol;

myScaleMarks.SubdivisionMarkHeight = this.SubdivisionMarkHeight;

ILineSymbol mySubdivisionMarkSymbol = new SimpleLineSymbolClass();

mySubdivisionMarkSymbol.Color = new RgbColorClass() { Red = 0, Green = 0, Blue = 0 };

mySubdivisionMarkSymbol.Width = this.SubdivisionMarkWidth;

myScaleMarks.SubdivisionMarkSymbol = mySubdivisionMarkSymbol;

IElement myElement = this._MapSurroundFrame as IElement;

IGeometry myGeometry = myElement.Geometry;

if (myGeometry != null && myGeometry.IsEmpty == false)

{

    IEnvelope myGeometryEnvelope = myGeometry.Envelope;

    this.Width = myGeometryEnvelope.Width;

    this.Height = myGeometryEnvelope.Height;

}

IEnvelope myEnvelope = new EnvelopeClass();

myEnvelope.PutCoords(this.X, this.Y, this.X + this.Width, this.Y + this.Height);

myElement.Geometry = myEnvelope;

myGraphicsContainer.AddElement(this._MapSurroundFrame as IElement, 0);

/// <summary>

/// 创建比例尺

/// </summary>

private IScaleBar CreateScaleBar()

{

    IScaleBar myScaleBar;

    if (this.BarType == "AlternatingScaleBar")

    {

        myScaleBar = new AlternatingScaleBar();

    }

    else if (this.BarType == "DoubleAlternatingScaleBar")

    {

        myScaleBar = new DoubleAlternatingScaleBar();

    }

    else if (this.BarType == "HollowScaleBar")

    {

        myScaleBar = new HollowScaleBar();

    }

    else if (this.BarType == "SteppedScaleLine")

    {

        myScaleBar = new SteppedScaleLine();

    }

    else

    {

        myScaleBar = new ScaleLine();

    }

    myScaleBar.Name = this.BarType;

    return myScaleBar;

}

3、普通Element

继承IElement接口的类如下图所示。

这个列表中的Elment，除了MapFrame、MapSurroundFrame以及后面带()的外，其他的基本上都是我们常用的，例如点元素、线元素、面元素、圆元素、椭圆元素、各种图片元素等。

IElement有一个关键属性Geometry，如果是MarkerElement或者TextElement，那么Geometry就是IPoint类型，如果是LineElement，那么Geometry是IPolyline类型，PolygonElement的Geometry为IPolygon类型，图片Element一般传入IEnvelope。

一些特殊的Element例如椭圆的Geometry传什么呢？这样不确定的问题，我们可以去SDK帮助中查找，一般帮助中会解释的很清楚。

帮助中说的比较明确，可以传递IEnvelope，这样会在IEnvelope生成 一个椭圆。也可以传由EllipticArc组成的Polygon对象。不过我们一般会传IEnvelope，主要原因是简单直观。

除了Geometry外，很对图形状的元素包含Symbol属性。例如MarkerElement可设置IMarkerSymbol，TextElement可以设置ITextSymbol，IPolylineElement可设置ILineSymbol，PolygonElement、CircleElement和EllipseElement可以设置IFillSymbol。

ArcObjects SDK开发 014 MapSurround和普通Element的相关教程结束。