'In this case, we could have set pEnvelope toIActiveView::Extent 'Set pEnvelope = pActiveView.Extent Set pCenterPoint = New Point

pCenterPoint.x= ((pEnvelope.XMax - pEnvelope.XMin) / 2) + pEnvelope.XMin pCenterPoint.y= ((pEnvelope.YMax - pEnvelope.YMin) / 2) + pEnvelope.YMin pEnvelope.width= pEnvelope.width / 2 pEnvelope.height= pEnvelope.height / 2 pEnvelope.CenterAtpCenterPoint pDisplayTransform.VisibleBounds= pEnvelope pActiveView.Refresh End Sub

=============================== 怎样读取一个字段内的所有值： ===============================

IFeatureClass pFC= m_SDEQuery.getFeatureClass(); IFeatureCursor pFeaCur= pFC.Search(null, false); IFeature pFeature= pFeaCur.NextFeature();

int pFieldIndex = pFC.Fields.FindField(this.m_cboQryFld.SelectedItem.Value.ToString()); System.Collections.ArrayListpArr = new System.Collections.ArrayList(); while (pFeature != null) {

string theFieldValue = pFeature.get_Value(pFieldIndex).ToString(); if (!pArr.Contains(theFieldValue)&& (theFieldValue.Trim() != \ {

m_cboQryText.Items.Add(theFieldValue); pArr.Add(theFieldValue); }

pFeature = pFeaCur.NextFeature(); }

=============================== 怎样编辑更改属性字段的值： ===============================

IRow prow = (IRow)bendiFeatureC.GetFeature(1);

MessageBox.Show(prow.Table.Fields.FieldCount.ToString());

ITable ptable = (ITable)bendiFeatureC; IQueryFilter pqfilter= new QueryFilterClass(); pqfilter.WhereClause = \北江路南郊一公里\\'\

IFeatureCursor pfeatcur;

pfeatcur = bendiFeatureC.Search(pqfilter, false);

IFeature pfff = pfeatcur.NextFeature(); while (pfff != null) {

IRowprrr = (IRow)pfff;

prrr.set_Value(prrr.Fields.FindField(\北江路南郊二公里\ pfff = (IFeature)prrr; pfff.Store();

pfff = pfeatcur.NextFeature(); }

===============================

怎样将MapControl中的Map复制到PageLayoutControl中 ===============================

Public Sub CopyAndOverwriteMap()

OnErrorGoToCopyAndOverwriteMap_err

DimpObjectCopyAsIObjectCopy pObjectCopy = New ObjectCopy

DimpToCopyMapAsObject

pToCopyMap = frmMap.AxMapControl1.Map

DimpCopiedMapAsObject

pCopiedMap = pObjectCopy.Copy(pToCopyMap)

DimpToOverwriteMapAsObject

pToOverwriteMap =PrintPageLayout.AxPageLayoutControl1.ActiveView.FocusMap

pObjectCopy.Overwrite(pCopiedMap, pToOverwriteMap) frmMap.AxMapControl1.MousePointer

=ESRI.ArcGIS.Controls.esriControlsMousePointer.esriPointerArrow frmMain.StatusMessage.Text = \ PrintPageLayout.ShowDialog() ExitSub

CopyAndOverwriteMap_err: MsgBox(Err.Number& \ - \&Err.Description,MsgBoxStyle.Critical,Application.ProductName& \- CopyMap\ ExitSub

End Sub

=============================== 怎样判断是否出于编辑状态： ===============================

If m_pEditor.EditState =esriStateEditingThen m_pEditor.StartOperation

'删除冗余节点

DelSubPoint pMap m_pEditor.StopOperation\ End If

把m_pEditor.StartOperation放在函数里面更好

=============================== 怎样用点创建一个Polygon： ===============================

Dim pPnt0 asIPoint,pPnt1asIPoint,pPnt2asIPoint Set pPnt0 = NewPoint Set pPnt1 = NewPoint Set pPnt2 = NewPoint pPnt0.PutCoordsx1,y1 pPnt1.PutCoordsx2,y2 pPnt2.PutCoordsx3,y3

Dim pPolygon as IPointCollection(注意，这里的polygon是设置为点集的) Set pPolygon =New Polygon pPolygon.AddPointpPnt0 pPolygon.AddPointpPnt1 pPolygon.AddPointpPnt2

pPolygon.AddPoint pPnt0(注意，这里一定要闭合回到pPnt0才能形成一个Polygon)

Set pFeature.Shape = pPolygon pFeature.Store

用这种方法可以创建一个Polyline：

Dim pPolyline asIPointCollection Set pPolyline =New Line pPolyline.AddPointpPnt0 pPolyline.AddPointpPnt1

pPolyline.AddPointpPnt2(这时就是一个polyline，不是闭合的)

还可以用另外一种方法，画一条两点之间的线段：

Dim pLine AsILine

Set pLine = New esriGeometry.Line

pLine.PutCoords pPnt0,pPnt1(第一个为from点，第二个为to点) )

=============================== 怎样运用属性来计算总面积： ===============================

Dim pDoc As IMxDocument Dim pMap As IMap

Dim pFeatureLayer As IFeatureLayer Dim pFeatureClass As IFeatureClass

Set pDoc = m_pApplication.Document Set pMap = pDoc.ActiveView.FocusMap Set pFeatureLayer = pMap.Layer(0)

Set pFeatureClass = pFeatureLayer.FeatureClass

' +++ create the query filter, and give

' +++ it a where clause Dim pQueryFilt As IQueryFilter Dim pFeatureCursor As IFeatureCursor

Set pQueryFilt = New QueryFilter pQueryFilt.WhereClause= \ 'COM'\

Set pFeatureCursor =pFeatureClass.Search(pQueryFilt, False)

' +++ get the area field Dim pFields As IFields Dim pField As IField Dim lAIndex As Long

Set pFields = pFeatureClass.Fields lAIndex = pFields.FindField(\ Set pField = pFields.Field(lAIndex)

' +++ a variable to hold the total area Dim dtotArea As Double dtotArea = 0#

' +++ loop through all of the features and ' +++ calculate the sum of all of the areas Dim pFeature As IFeature

Set pFeature = pFeatureCursor.NextFeature Do

dtotArea = dtotArea + pFeature.Value(lAIndex) Set pFeature = pFeatureCursor.NextFeature Loop Until pFeature Is Nothing

' +++ send the total area to a message box MsgBox dtotArea

=============================== 关于属性域的一些心得 ===============================