ArcEngine 创建线要素图层

Dim objectClassDescription As IObjectClassDescription = New FeatureClassDescription
Dim fields2 As Fields = objectClassDescription.RequiredFields

 Dim featureClassName As String = "图层名称" ‘临时图层名称
        Dim workspaceFactory As IWorkspaceFactory = New InMemoryWorkspaceFactory() ‘内存空间
        Dim WorkspaceName As IWorkspaceName = workspaceFactory.Create("", "MyWorkspace", Nothing, 0)
        Dim name As IName = WorkspaceName
        Dim workspace As IWorkspace = name.Open()
        Dim featureWorkspace As IFeatureWorkspace = workspace

        ‘Dim workspace2 As IWorkspace2 = workspace
        Dim fields As IFields = Nothing
        Dim CLSID As ESRI.ArcGIS.esriSystem.UID = Nothing
        Dim CLSEXT As ESRI.ArcGIS.esriSystem.UID = Nothing
        Dim strConfigKeyword As String = ""
        Dim featureClass As IFeatureClass
        ‘ 赋值类ID如果未分配
        If CLSID Is Nothing Then
            CLSID = New ESRI.ArcGIS.esriSystem.UID
            CLSID.Value = "esriGeoDatabase.Feature"
        End If
        ‘环境默认生成的两个字段，字段的几何类型为Polygon,决定了要素图层的集合类型
        ‘Dim objectClassDescription As IObjectClassDescription = New FeatureClassDescription
        ‘Dim fields2 As Fields = objectClassDescription.RequiredFields
        If fields Is Nothing Then
            ‘ 创建要素几何信息
            Dim pGeometryDef As IGeometryDef = New GeometryDef() ‘ 为esriFieldTypeGeometry类型的字段创建几何定义，包括类型和空间参照    
            Dim pGeometryDefEdit As IGeometryDefEdit = pGeometryDef
            pGeometryDefEdit.GridCount_2 = 1
            pGeometryDefEdit.GeometryType_2 = ESRI.ArcGIS.Geometry.esriGeometryType.esriGeometryPolyline ‘决定要素图层的几何类型
            pGeometryDefEdit.SpatialReference_2 = pMap.SpatialReference

            fields = New Fields
            Dim fieldsEdit As IFieldsEdit = CType(fields, IFieldsEdit)
            ‘自己创建OBJECTID字段
            Dim fieldOID As IField = New Field()
            Dim fieldEditOID As IFieldEdit = CType(fieldOID, IFieldEdit)
            fieldEditOID.Name_2 = "OBJECTID"
            fieldEditOID.AliasName_2 = "OBJECTID"
            fieldEditOID.Type_2 = esriFieldType.esriFieldTypeOID
            fieldEditOID.Editable_2 = False
            fieldsEdit.AddField(fieldOID)

            ‘自己创建几何字段，
            Dim fieldShape As IField = New Field()
            Dim fieldEditShape As IFieldEdit = CType(fieldShape, IFieldEdit)
            fieldEditShape.Name_2 = "SHAPE"
            fieldEditShape.AliasName_2 = "SHAPE"
            fieldEditShape.Type_2 = esriFieldType.esriFieldTypeGeometry
            fieldEditShape.GeometryDef_2 = pGeometryDef
            fieldEditShape.Editable_2 = True
            fieldsEdit.AddField(fieldShape)



            Dim field As IField = New Field
            Dim fieldEdit As IFieldEdit = CType(field, IFieldEdit) ‘ 显示转换
            ‘ 设置字段属性
            fieldEdit.Name_2 = "RISK"
            fieldEdit.Type_2 = esriFieldType.esriFieldTypeDouble
            fieldEdit.IsNullable_2 = False
            fieldEdit.AliasName_2 = "RISK"
            fieldEdit.DefaultValue_2 = 0
            fieldEdit.Editable_2 = True
            fieldEdit.Type_2 = esriFieldType.esriFieldTypeGeometry
            fieldsEdit.AddField(field)
            Dim field2 As IField = New Field
            Dim fieldEdit2 As IFieldEdit = CType(field2, IFieldEdit) ‘ 显示转换
            ‘ 设置字段属性
            fieldEdit2.Name_2 = "管线ObjId"
            fieldEdit2.Type_2 = esriFieldType.esriFieldTypeInteger
            fieldEdit2.IsNullable_2 = False
            fieldEdit2.AliasName_2 = "管线ObjId"
            fieldEdit2.DefaultValue_2 = 0
            fieldEdit2.Editable_2 = True
            ‘添加到字段集中
            fieldsEdit.AddField(field2)
            fields = CType(fieldsEdit, IFields)
        End If
        Dim strShapeField As String = ""
        Dim j As Int32
        For j = 0 To fields.FieldCount
            If fields.Field(j).Type = esriFieldType.esriFieldTypeGeometry Then
                strShapeField = fields.Field(j).Name
                ‘fields.Field(j).GeometryDef.GeometryType = ESRI.ArcGIS.Geometry.esriGeometryType.esriGeometryPolyline
                Exit For
            End If
        Next j
        Dim fieldChecker As IFieldChecker = New FieldChecker
        Dim enumFieldError As IEnumFieldError = Nothing
        Dim validatedFields As IFields = Nothing
        fieldChecker.ValidateWorkspace = workspace
        fieldChecker.Validate(fields, enumFieldError, validatedFields)
        featureClass = featureWorkspace.CreateFeatureClass(featureClassName, validatedFields, CLSID, CLSEXT, esriFeatureType.esriFTSimple, strShapeField, strConfigKeyword)