基于ArcGIS10.0和Oracle10g的空间数据管理平台十三（C#开发）-空

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前面有几篇文章专门介绍了空间数据的导入，导入的目的是为了统一管理。今天介绍空间数据导出，导出的格式支持和导入的格式一样，导出的目的是为了方便数据的迁移。其实导入和导出用到的技术基本上都是相同的，不过为了介绍的完整性还是单独拿出来，因为这一部分的功能也是很重要而且是必不可少的！

1.首先定义一个用于操作SDE数据库的工作空间并且在构造函数中初始化（调用工具类里面提供的静态方法初始化）：

        private IFeatureWorkspace pWorkspaceSDE;//定义SDE工作空间
         public FrmDataExport()
        {
            InitializeComponent();
            if (pWorkspaceSDE == null)
            {
                pWorkspaceSDE = MapOperation.GetFeatrueWorkspace();
            }
        }

2.列出所有数据表：供用户选择需要导出的数据，每一个表是一个可选项，这样用户可以一次导出多个需要的数据表。

        /// <summary>
        /// 列出所有的表信息
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void FrmDataExport_Load(object sender, EventArgs e)
        {
            SqlHelper sh = new SqlHelper();
            string sql = string.Empty;
            sql = "select table_name,table_mapname,type from layer l,element e where "
                + "e.id=l.pid and e.category='矢量数据'";
            OracleDataReader odr = sh.ReturnDataReader(sql);
            object[] obj = new object[4];
            while (odr.Read())
            {
                obj[0] = false;
                obj[1] = odr[0].ToString();
                obj[2] = odr[2].ToString();
                obj[3] = odr[1].ToString();
                dataGridViewX1.Rows.Add(obj);
            }
            comboBoxEx1.SelectedIndex = 0;
        }

3.根据选择的导出数据格式打开相应的文件

        /// <summary>
        /// 根据选择的导出数据格式打开相应的文件
         /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void selectPathBtn_Click(object sender, EventArgs e)
        {
            //根据导出数据格式打开相应的文件
            switch (comboBoxEx1.SelectedIndex)
            {
                case 0:
                    {
                        FolderBrowserDialog folder = new FolderBrowserDialog();
                        if (folder.ShowDialog() == DialogResult.OK)
                        {
                            if (folder.SelectedPath != "")
                            {
                                selectPathTxt.Text = folder.SelectedPath;
                            }
                        }
                    }
                    break;
                case 1:
                    { 
                        OpenFileDialog ofd = new OpenFileDialog();
                        ofd.Filter = "MDB文件(.mdb) | *.mdb";
                        ofd.CheckFileExists = false;

                        if (ofd.ShowDialog() == DialogResult.OK)
                        {
                            
                            if (ofd.FileName != "")
                            {
                                selectPathTxt.Text = ofd.FileName;
                            }
                        }
                    }
                    break;
                default:
                    break;
            }
        }

4.执行具体的导出功能：一起准备工作都做好了就开始执行具体的导出功能了，根据不同的格式执行相应导出格式的功能。

        /// <summary>
        /// 执行具体的导出功能
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void exportBtn_Click(object sender, EventArgs e)
        {
            if (selectPathTxt.Text == "")
            {
                MessageBox.Show("请选择导出路劲");
                return;
            }
            IWorkspaceFactory pWF = null;
            switch (comboBoxEx1.SelectedIndex)
            {
                case 0:
                    {
                        if (!File.Exists(selectPathTxt.Text))
                        {
                            
                        }
                        //创建一个输出shp文件的工作空间
                        pWF = new ShapefileWorkspaceFactoryClass();
                        IFeatureWorkspace pFW = pWF.OpenFromFile(selectPathTxt.Text, 0) as IFeatureWorkspace;
                        IWorkspace pW = pFW as IWorkspace;

                        for (int i = 0; i < dataGridViewX1.Rows.Count; ++i)
                        {
                            if (bool.Parse(dataGridViewX1.Rows[i].Cells[0].Value.ToString()))
                            {
                                if (dataGridViewX1.Rows[i].Cells[2].Value.ToString() != "PA")
                                {
                                    string str = dataGridViewX1.Rows[i].Cells[1].Value.ToString();
                                    MapOperation.ConvertFeatureClass(pWorkspaceSDE as IWorkspace,
                                        pW, str, str, 4326);
                                } 
                                else
                                {
                                    MessageBox.Show("属性表不能够导出为Shape文件");
                                }
                            }
                        }
                        MessageBox.Show("导出数据完成!");
                    }
                    break;
                case 1:
                    {
                        // Instantiate an Access workspace factory and create a new personal geodatabase.
                        pWF = new AccessWorkspaceFactoryClass();
                        IWorkspaceName pWN = pWF.Create(Path.GetDirectoryName(selectPathTxt.Text),
                             Path.GetFileName(selectPathTxt.Text),null, 0);

                        // Cast the workspace name object to the IName interface and open the workspace.
                        IName pN = (IName)pWN;
                        IWorkspace pW = (IWorkspace)pN.Open();

                        for (int i = 0; i < dataGridViewX1.Rows.Count; ++i)
                        {
                            if (bool.Parse(dataGridViewX1.Rows[i].Cells[0].Value.ToString()))
                            {
                                string str = dataGridViewX1.Rows[i].Cells[1].Value.ToString();
                                if (dataGridViewX1.Rows[i].Cells[2].Value.ToString() != "PA")
                                {
                                    MapOperation.ConvertFeatureClass(pWorkspaceSDE as IWorkspace,
                                       pW, str, str, 4326);
                                } 
                                else
                                {
                                    ITable pSourceT = pWorkspaceSDE.OpenTable(str);
                                    IFeatureWorkspace pFW = pW as IFeatureWorkspace;
                                    ITable pTargetT = pFW.CreateTable(str, pSourceT.Fields, null, null, "");
                                    FusedIndexTable(ref pSourceT, ref pTargetT);
                                }
                            }
                        }
                        MessageBox.Show("导出数据完成!");
                    }
                    break;
                default:
                    break;
            }
        }

5.如果导出的数据表或文件已经存在就以追加的方式导出数据

        /// <summary>
        /// 如果目的数据库中已经有表，则将新的记录追加进去 
        /// </summary>
        /// <param name="FromTable">导出表</param>
        /// <param name="ToTable">导入表</param>
        private void FusedIndexTable(ref ITable FromTable, ref ITable ToTable)
        {
            if (FromTable == null || ToTable == null)
            {
                return;
            }
            IRow pFromRow;
            ICursor pToCursor, pFromCursor;
            IRowBuffer pToRowBuffer;
            int pIndex;

            pToRowBuffer = ToTable.CreateRowBuffer();
            pToCursor = ToTable.Insert(true);
            pFromCursor = FromTable.Search(null, false);
            pFromRow = pFromCursor.NextRow();
            while (pFromRow != null)
            {
                for (int i = 0; i < pFromRow.Fields.FieldCount; i++)
                {
                    pIndex = pToRowBuffer.Fields.FindField(pFromRow.Fields.get_Field(i).Name.Trim());
                    if (pFromRow.Fields.get_Field(i).Editable && pIndex > -1)
                    {
                        pToRowBuffer.set_Value(pIndex, pFromRow.get_Value(i));
                    }
                }

                pToCursor.InsertRow(pToRowBuffer);
                pFromRow = pFromCursor.NextRow();
            }
            System.Runtime.InteropServices.Marshal.ReleaseComObject(pToCursor);
            pFromRow = null;
            pFromCursor = null;
            pToRowBuffer = null;
        }
    }

6.总结：这里用到的大部分技术在前面都介绍过了，这里不过是不同的业务逻辑而已，其实很多的时候高深的技术并不会用到很多，主要是处理好各个功能的业务逻辑，至于用什么样的技术实现都是可以的！