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ArcObjects - 枚举地理数据库中的要素类和数据集

发布于 2024-08-26 13:48:30 字数 196 浏览 7 评论 0原文

我正在尝试使用 vba/arcobjects 枚举文件地理数据库的内容（要素类和要素数据集，对表不感兴趣等）。

我将文件 GDB 设置为 IGxDatabase 对象，但找不到进一步深入的方法。我查看了地理数据库对象模型并尝试使用 IFeatureClass 和 IFeatureDataset，但似乎都没有返回有用的结果。

预先感谢您的任何帮助

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四叶草在未来唯美盛开 2024-09-02 13:48:30

枚举地理数据库中包含的名称比枚举名称可以打开的内容要快得多。棘手的部分是循环遍历特征数据集中的名称。虽然 IFeatureWorkspace.Open 可用于打开要素类，而无需先打开包含它的要素数据集，但获取要素数据集中的要素类名称需要打开要素数据集。

如果您确定需要打开每个要素类，那么我想使用 IWorkspace.Datasets、IEnumDataset 和 IDataset 而不是 IWorkspaceDatasetNames、IEnumDatasetname 和 IDatasetname 不会有什么坏处。


Option Explicit
Sub TestGetContents()
    Dim pGxApp As IGxApplication
    Set pGxApp = Application
    If Not TypeOf pGxApp.SelectedObject Is IGxDatabase Then
        Debug.Print "select a geodb first"
        Exit Sub
    End If
    Dim c As Collection
    Set c = GetContents(pGxApp.SelectedObject)
    Dim l As Long
    For l = 1 To c.Count
        Dim pName As IName
        Set pName = c.Item(l)
        If TypeOf pName Is IFeatureClassName Then
            Dim pFC As IFeatureClass
            Set pFC = pName.Open
            Debug.Print pFC.AliasName, pFC.FeatureCount(Nothing)
        ElseIf TypeOf pName Is IFeatureDatasetName Then
            Dim pDSName As IDatasetName
            Set pDSName = pName
            Debug.Print pDSName.name, "(featuredataset)"
        End If
    Next l
End Sub

函数 GetContents(pGxDB As IGxDatabase) 作为集合
    Dim c 作为新系列
    Dim pEnumDSName As IEnumDatasetName
    设置 pEnumDSName = pGxDB.Workspace.DatasetNames(esriDTAny)
    Dim pDSName As IDatasetName
    设置 pDSName = pEnumDSName.Next
    执行直至 pDSName 为空
        如果 TypeOf pDSName 是 IFeatureClassName 那么
            c.添加pDSName
        ElseIf TypeOf pDSName 是 IFeatureDatasetName 那么
            c.添加pDSName
            AddSubNames pDSName, c
        结束如果
        设置 pDSName = pEnumDSName.Next
    环形
    设置 GetContents = c
End Function

 Sub AddSubNames(pDSName1 As IDatasetName, c As Collection)
    Dim pEnumDSName As IEnumDatasetName
    设置 pEnumDSName = pDSName1.SubsetNames
    pEnumDSName.重置
    将 pDSName2 调暗为 IDatasetName
    设置 pDSName2 = pEnumDSName.Next
    执行此操作直至 pDSName2 不再存在
        如果 TypeOf pDSName2 是 IFeatureClassName 那么
            c.添加pDSName2
        结束如果
        设置 pDSName2 = pEnumDSName.Next
    环形
结束子

It is much faster to enumerate the names contained in a geodatabase instead of the things that the names can open. The tricky part is looping through names in a featuredataset. While IFeatureWorkspace.Open can be used to open a featureclass without first opening the featuredataset that contains it, getting at featureclassnames within a featuredataset requires opening the featuredataset.

If you know for sure you'll need to open each featureclass, then I suppose it wouldn't hurt to use IWorkspace.Datasets, IEnumDataset, and IDataset instead of IWorkspaceDatasetNames, IEnumDatasetname and IDatasetname.


Option Explicit
Sub TestGetContents()
    Dim pGxApp As IGxApplication
    Set pGxApp = Application
    If Not TypeOf pGxApp.SelectedObject Is IGxDatabase Then
        Debug.Print "select a geodb first"
        Exit Sub
    End If
    Dim c As Collection
    Set c = GetContents(pGxApp.SelectedObject)
    Dim l As Long
    For l = 1 To c.Count
        Dim pName As IName
        Set pName = c.Item(l)
        If TypeOf pName Is IFeatureClassName Then
            Dim pFC As IFeatureClass
            Set pFC = pName.Open
            Debug.Print pFC.AliasName, pFC.FeatureCount(Nothing)
        ElseIf TypeOf pName Is IFeatureDatasetName Then
            Dim pDSName As IDatasetName
            Set pDSName = pName
            Debug.Print pDSName.name, "(featuredataset)"
        End If
    Next l
End Sub

Function GetContents(pGxDB As IGxDatabase) As Collection
    Dim c As New Collection
    Dim pEnumDSName As IEnumDatasetName
    Set pEnumDSName = pGxDB.Workspace.DatasetNames(esriDTAny)
    Dim pDSName As IDatasetName
    Set pDSName = pEnumDSName.Next
    Do Until pDSName Is Nothing
        If TypeOf pDSName Is IFeatureClassName Then
            c.Add pDSName
        ElseIf TypeOf pDSName Is IFeatureDatasetName Then
            c.Add pDSName
            AddSubNames pDSName, c
        End If
        Set pDSName = pEnumDSName.Next
    Loop
    Set GetContents = c
End Function

Sub AddSubNames(pDSName1 As IDatasetName, c As Collection)
    Dim pEnumDSName As IEnumDatasetName
    Set pEnumDSName = pDSName1.SubsetNames
    pEnumDSName.Reset
    Dim pDSName2 As IDatasetName
    Set pDSName2 = pEnumDSName.Next
    Do Until pDSName2 Is Nothing
        If TypeOf pDSName2 Is IFeatureClassName Then
            c.Add pDSName2
        End If
        Set pDSName2 = pEnumDSName.Next
    Loop
End Sub

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凶凌 2024-09-02 13:48:30

您可以在地理处理器上使用 ListFeatureClasses 方法
（下面展示了如何在 C# 中完成此操作）

IGeoProcessor gp = new GeoProcessorClass(); 

gp.SetEnvironmentValue("workspace", @"C:\temp"); 

IGpEnumList gpEnumList = gp.ListFeatureClasses("*", "Polygon", ""); 
string fc = gpEnumList.Next(); 
while (fc != "") 
{ 
//Do whatever
}

you can use the ListFeatureClasses Method on the Geoprocessor
(the following shows how this can be done in C#)

IGeoProcessor gp = new GeoProcessorClass(); 

gp.SetEnvironmentValue("workspace", @"C:\temp"); 

IGpEnumList gpEnumList = gp.ListFeatureClasses("*", "Polygon", ""); 
string fc = gpEnumList.Next(); 
while (fc != "") 
{ 
//Do whatever
}

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~没有更多了~