基于c#/Arcgis Engine开发时，从ArcCatalog拖放（DragDrog）数据集至TextBox的实现

原文：http://www.samuelbosch.com/2009/06/drag-drop-from-arccatalog.html

帮助类：using System.Collections.Generic;
using System.Windows.Forms;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.SystemUI;

namespace GisSolved.DragDrop
{
public class EsriDragDrop
{
const string DATAOBJECT_ESRINAMES = "ESRI Names";
public static bool IsValid(IDataObject dataObject)
{
return dataObject.GetDataPresent(DATAOBJECT_ESRINAMES) ||
dataObject.GetDataPresent(System.Windows.Forms.DataFormats.FileDrop);
}
public static List<string> GetPaths(IDataObject dataObject)
{
List<string> foundPaths = new List<string>();
IDataObjectHelper dataObjectHelper = new DataObjectHelperClass();
dataObjectHelper.InternalObject = (object)dataObject;

if (dataObjectHelper.CanGetNames())
{
IEnumName enumNames = dataObjectHelper.GetNames();
IName name;
while ((name = enumNames.Next()) != null)
{
if (name is IDatasetName)
{
IDatasetName datasetName = (IDatasetName)name;
// only accept feature classes and tables
if (datasetName.Type == esriDatasetType.esriDTFeatureClass ||
datasetName.Type == esriDatasetType.esriDTTable)
{
string path = System.IO.Path.Combine(datasetName.WorkspaceName.PathName, datasetName.Name);
foundPaths.Add(path);
}
// 还可以判断其他的类型
// else if (name is ...) { }
}
}
}
else if (dataObjectHelper.CanGetFiles())
{
string[] paths = (string[])dataObjectHelper.GetFiles();
foreach (string path in paths)
{
// TODO : Add code here to check if the file path is a valid path
foundPaths.Add(path);
}
}
return foundPaths;
}
}
}

TextBox要设置AllowDrag = true，并且设置两个事件：_DragEnter（拖放数据进来时的判断）、_DragDrop（拖放鼠标放开时的事件），代码如下：

private void TextBoxPath_DragEnter(object sender, DragEventArgs e)
{
e.Effect = EsriDragDrop.IsValid(e.Data) ? DragDropEffects.All : DragDropEffects.None; // 判断是从Arcgis拖放来的数据才允许
}

private void TextBoxPath_DragDrop(object sender, DragEventArgs e)
{
List<string> paths = EsriDragDrop.GetPaths(e.Data); // 获得拖放过来的数据集的路径
}