AE开发示例之GPBufferLayer

using System;

using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using ESRI.ArcGIS.ADF.BaseClasses;
using ESRI.ArcGIS.ADF.CATIDs;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Geoprocessor;
using ESRI.ArcGIS.Geoprocessing;
using ESRI.ArcGIS.AnalysisTools;

namespace GpBufferLayer
{
public partial class BufferDlg : Form
{
//in order to scroll the messages textbox to the bottom we must import this Win32 call
[DllImport("user32.dll")]
private static extern int PostMessage(IntPtr wnd,
uint Msg,
IntPtr wParam,
IntPtr lParam);

private IHookHelper m_hookHelper = null;
private const uint WM_VSCROLL = 0x0115;
private const uint SB_BOTTOM = 7;

public BufferDlg(IHookHelper hookHelper)
{
InitializeComponent();

m_hookHelper = hookHelper;
}

private void bufferDlg_Load(object sender, EventArgs e)
{
if (null == m_hookHelper || null == m_hookHelper.Hook || 0 == m_hookHelper.FocusMap.LayerCount)
return;

//load all the feature layers in the map to the layers combo
IEnumLayer layers = GetLayers();
layers.Reset();
ILayer layer = null;
while ((layer = layers.Next()) != null)
{
cboLayers.Items.Add(layer.Name);
}
//select the first layer
if (cboLayers.Items.Count > 0)
cboLayers.SelectedIndex = 0;

string tempDir = System.IO.Path.GetTempPath();
txtOutputPath.Text = System.IO.Path.Combine(tempDir,((string)cboLayers.SelectedItem + "_buffer.shp"));

//set the default units of the buffer
int units = Convert.ToInt32(m_hookHelper.FocusMap.MapUnits);
cboUnits.SelectedIndex = units;
}

private void btnOutputLayer_Click(object sender, EventArgs e)
{
//set the output layer
SaveFileDialog saveDlg = new SaveFileDialog();
saveDlg.CheckPathExists = true;
saveDlg.Filter = "Shapefile (*.shp)|*.shp";
saveDlg.OverwritePrompt = true;
saveDlg.Title = "Output Layer";
saveDlg.RestoreDirectory = true;
saveDlg.FileName = (string)cboLayers.SelectedItem + "_buffer.shp";

DialogResult dr = saveDlg.ShowDialog();
if (dr == DialogResult.OK)
txtOutputPath.Text = saveDlg.FileName;
}

private void btnBuffer_Click(object sender, EventArgs e)
{
//make sure that all parameters are okay
double bufferDistance;
double.TryParse(txtBufferDistance.Text, out bufferDistance);
if (0.0 == bufferDistance)
{
MessageBox.Show("Bad buffer distance!");
return;
}

if (!System.IO.Directory.Exists(System.IO.Path.GetDirectoryName(txtOutputPath.Text)) ||
".shp" != System.IO.Path.GetExtension(txtOutputPath.Text))
{
MessageBox.Show("Bad output filename!");
return;
}

if (m_hookHelper.FocusMap.LayerCount == 0)
return;

//get the layer from the map
IFeatureLayer layer = GetFeatureLayer((string)cboLayers.SelectedItem);
if (null == layer)
{
txtMessages.Text += "Layer " + (string)cboLayers.SelectedItem + "cannot be found!\r\n";
return;
}

//scroll the textbox to the bottom
ScrollToBottom();
//add message to the messages box
txtMessages.Text += "Buffering layer: " + layer.Name + "\r\n";

txtMessages.Text += "\r\nGet the geoprocessor. This might take a few seconds...\r\n";
txtMessages.Update();
//get an instance of the geoprocessor
Geoprocessor gp = new Geoprocessor();
gp.OverwriteOutput = true;
txtMessages.Text += "Buffering...\r\n";
txtMessages.Update();

//create a new instance of a buffer tool
ESRI.ArcGIS.AnalysisTools.Buffer buffer = new ESRI.ArcGIS.AnalysisTools.Buffer(layer, txtOutputPath.Text, Convert.ToString(bufferDistance) + " " + (string)cboUnits.SelectedItem);

//execute the buffer tool (very easy :-))
IGeoProcessorResult results = (IGeoProcessorResult)gp.Execute(buffer, null);
if (results.Status != esriJobStatus.esriJobSucceeded)
{
txtMessages.Text += "Failed to buffer layer: " + layer.Name + "\r\n";
}
txtMessages.Text += ReturnMessages(gp);
//scroll the textbox to the bottom
ScrollToBottom();

txtMessages.Text += "\r\nDone.\r\n";
txtMessages.Text += "-----------------------------------------------------------------------------------------\r\n";
//scroll the textbox to the bottom
ScrollToBottom();

}

private string ReturnMessages(Geoprocessor gp)
{
StringBuilder sb = new StringBuilder();
if (gp.MessageCount > 0)
{
for (int Count = 0; Count <= gp.MessageCount - 1; Count++)
{
System.Diagnostics.Trace.WriteLine(gp.GetMessage(Count));
sb.AppendFormat("{0}\n", gp.GetMessage(Count));
}
}
return sb.ToString();
}

private IFeatureLayer GetFeatureLayer(string layerName)
{
//get the layers from the maps
IEnumLayer layers = GetLayers();
layers.Reset();

ILayer layer = null;
while ((layer = layers.Next()) != null)
{
if (layer.Name == layerName)
return layer as IFeatureLayer;
}

return null;
}

private IEnumLayer GetLayers()
{
UID uid = new UIDClass();
uid.Value = "{40A9E885-5533-11d0-98BE-00805F7CED21}";
IEnumLayer layers = m_hookHelper.FocusMap.get_Layers(uid, true);

return layers;
}

private void ScrollToBottom()
{
PostMessage((IntPtr)txtMessages.Handle, WM_VSCROLL, (IntPtr)SB_BOTTOM, (IntPtr)IntPtr.Zero);
}
private void btnCancel_Click(object sender, EventArgs e)
{
this.Close();
}
}
}