C#Arcengine判断GDB中是否有指定名的图层

可以使用 ArcObjects 中的 IWorkspace 和 IEnumDataset 接口来实现判断 GDB 中是否存在指定名称的图层。以下是C#代码示例：

//获取工作空间
IWorkspaceFactory workspaceFactory = new FileGDBWorkspaceFactory();
IWorkspace workspace = workspaceFactory.OpenFromFile("GDB路径", 0);

//遍历数据集获取所有图层
IEnumDataset enumDataset = workspace.get_Datasets(esriDatasetType.esriDTAny);
IDataset dataset = enumDataset.Next();
while(dataset != null)
{
    if(dataset.Type == esriDatasetType.esriDTFeatureClass)
    {
        //判断是否为指定名称的图层
        if(dataset.Name == "图层名称")
        {
            Console.WriteLine("存在指定名称的图层！");
            break;
        }
    }
    dataset = enumDataset.Next();
}

需要注意的是，该方法只能判断 GDB 中是否存在指定名称的图层，不能判断是否存在同名但不同类型的数据集。

相关问题

C#Arcengine打开GDB中指定名的图层

你可以使用C# ArcEngine中的以下代码打开GDB中指定名称的图层：

//打开工作空间
IWorkspaceFactory workspaceFactory = new FileGDBWorkspaceFactory();
IWorkspace workspace = workspaceFactory.OpenFromFile("C:\\data\\myGDB.gdb", 0);

//打开要素数据集
IFeatureWorkspace featureWorkspace = (IFeatureWorkspace)workspace;
IFeatureDataset featureDataset = featureWorkspace.OpenFeatureDataset("myFeatureDataset");

//打开要素类
IFeatureClass featureClass = featureDataset.OpenFeatureClass("myFeatureClass");

其中，`"C:\\data\\myGDB.gdb"` 是你的GDB文件路径，`"myFeatureDataset"` 是你的要素数据集名称，`"myFeatureClass"` 是你要打开的图层名称。你可以根据自己的实际情况修改这些参数。

C#arcengine更改GDB中要素数据集坐标系

在C# ArcEngine中更改GDB中要素数据集的坐标系，可以按照以下步骤操作：

1. 打开要素数据集所在的GDB文件：

IWorkspaceFactory workspaceFactory = new FileGDBWorkspaceFactory();
IWorkspace workspace = workspaceFactory.OpenFromFile(@"C:\data\myGDB.gdb", 0);

2. 获取要素数据集：

IFeatureWorkspace featureWorkspace = workspace as IFeatureWorkspace;
IFeatureDataset featureDataset = featureWorkspace.OpenFeatureDataset("myFeatureDataset");

3. 获取要素数据集的描述对象：

IDataset dataset = featureDataset as IDataset;
IObjectClassDescription objectClassDescription = new FeatureClassDescriptionClass();
IFields fields = null;
IUID uid = objectClassDescription.CLSID;
IEnumDataset enumDataset = featureDataset.Subsets;
enumDataset.Reset();
IDataset subsetDataset = enumDataset.Next();
while (subsetDataset != null)
{
    if (subsetDataset is IFeatureClass)
    {
        IFeatureClass featureClass = subsetDataset as IFeatureClass;
        if (featureClass.AliasName == "myFeatureClass")
        {
            fields = featureClass.Fields;
            uid = featureClass.ClassID;
            break;
        }
    }
    subsetDataset = enumDataset.Next();
}

4. 创建新的要素类，并设置其坐标系：

IFeatureClassDescription newFeatureClassDescription = new FeatureClassDescriptionClass();
IObjectClassDescription newObjectClassDescription = newFeatureClassDescription as IObjectClassDescription;
IFieldsEdit newFieldsEdit = new FieldsClass();
IFields newFields = fields;
newFieldsEdit.Clone(ref newFields);

IWorkspaceEdit workspaceEdit = workspace as IWorkspaceEdit;
bool hasParent = dataset.Category == "Feature Dataset";
IObjectClass newObjectClass = featureDataset.CreateFeatureClass("newFeatureClass", newFieldsEdit, uid, null, esriFeatureType.esriFTSimple, "SHAPE", "");
IDataset newDataset = newObjectClass as IDataset;
IGeoDataset geoDataset = newDataset as IGeoDataset;
ISpatialReferenceFactory spatialReferenceFactory = new SpatialReferenceEnvironmentClass();
ISpatialReference newSpatialReference = spatialReferenceFactory.CreateProjectedCoordinateSystem(3857); //设置新的坐标系
geoDataset.SpatialReference = newSpatialReference;

需要注意的是，更改坐标系可能会影响到数据的准确性和精度，建议在更改前备份数据并谨慎操作。