Arc Engine二次开发——弹窗进行属性查询

在Arcmap中使用Sapefile格式的矢量数据时，经常会用到其属性查询的功能，弹出窗体然后用户鼠标点击或手动输入查询条件，进而查询到感兴趣的要素。在AE二次开发中也经常需要这个功能，于是在此记录整个开发过程。

首先当然是需要构建一个Visual C# Windows窗体应用程序，然后添加axMapControl等控件，这些过程不再赘述。

然后新建一个名为FormQueryAttr.cs的窗体，用于属性查询时弹出，其界面设置为如下：

其中要素为：一个ComboBox（cboLayer）；两个ListBox（listBoxField和listBoxValue）；一个GroupBox；一个TextBox（textBoxSql）

21个Button，表达式所需的19个button的名称如下：

btnequal、btnunequal、btnis、btnlike、btnmore、btnless、btnmoe、btnloe、btnor、btnnull、btnnot、btnand、btnin、btnunderline、btnpercent、btncharacter、btnbetween、btnspace、btnempty

点击查看代码，添加以下变量并在构造函数中添加以下语句：

         //地图数据
         private AxMapControl mMapControl;
         //选中的图层
         private IFeatureLayer mFeatureLayer;
         //根据所选择的图层查询得到的特征类
         private IFeatureClass pFeatureClass = null;

         public FormQueryAttr(AxMapControl mapControl)
         {
             InitializeComponent();
             this.mMapControl = mapControl;
         }

接着回到程序主界面，添加属性查询的Button按钮，在其点击响应函数中添加如下代码：

         //属性查询
         private void barButtonItem13_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
         {
             FormQueryAttr formqueryattr = new FormQueryAttr(this.axMapControl1);
             formqueryattr.Show();
         }

至此，程序运行且用户点击“属性查询”按钮时，会初始化FormQueryAttr.cs窗体，将整个axMapControl作为参数传入，并显示窗体。

然后再回到FormQueryAttr.cs窗体的代码中，做以下更改：

在其Load函数中为cboLayer添加所有图层名称，代码如下：

         private void FormQueryAttr_Load(object sender, EventArgs e)
         {
             //MapControl中没有图层时返回
             if (this.mMapControl.LayerCount <= )
                 return;
             //获取MapControl中的全部图层名称，并加入ComboBox
             ILayer pLayer;
             //图层名称
             string strLayerName;
             for (int i = ; i < this.mMapControl.LayerCount; i++)
             {
                 pLayer = this.mMapControl.get_Layer(i);
                 strLayerName = pLayer.Name;
                 //图层名称加入cboLayer
                 this.cboLayer.Items.Add(strLayerName);
             }
             //默认显示第一个选项
             this.cboLayer.SelectedIndex = ;
         }

为cboLayer添加SelectedIndexChanged响应事件，其中代码如下：

         private void cboLayer_SelectedIndexChanged(object sender, EventArgs e)
         {
             this.listBoxField.Items.Clear();
             //获取cboLayer中选中的图层
             mFeatureLayer = mMapControl.get_Layer(cboLayer.SelectedIndex) as IFeatureLayer;
             pFeatureClass = mFeatureLayer.FeatureClass;
             string strFldName;
             for (int i = ; i < pFeatureClass.Fields.FieldCount; i++)
             {
                 strFldName = pFeatureClass.Fields.get_Field(i).Name;
                 this.listBoxField.Items.Add(strFldName);
             }
             this.listBoxField.SelectedIndex = ;
             this.label8.Text = mFeatureLayer.Name;
         }

为listBoxField添加SelectedIndexChanged和DoubleClick响应事件，其中代码如下：

         private void listBoxField_SelectedIndexChanged(object sender, EventArgs e)
         {
             string sFieldName = listBoxField.Text;
             listBoxValue.Items.Clear();
             int iFieldIndex = ;
             IField pField = null;
             IFeatureCursor pFeatCursor = pFeatureClass.Search(null, true);
             IFeature pFeat = pFeatCursor.NextFeature();
             iFieldIndex = pFeatureClass.FindField(sFieldName);
             pField = pFeatureClass.Fields.get_Field(iFieldIndex);
             while (pFeat != null)
             {
                 listBoxValue.Items.Add(pFeat.get_Value(iFieldIndex));
                 pFeat = pFeatCursor.NextFeature();
             }

         }
         private void listBoxField_DoubleClick(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = listBoxField.SelectedItem.ToString() + " ";
         }

为listBoxValue添加DoubleClick响应事件，其中代码如下：

         private void listBoxValue_DoubleClick(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = listBoxValue.SelectedItem.ToString() + " ";
         }

然后对“表达式”中的按钮添加对应的点击响应函数，具体代码如下：

         private void btnequal_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = "= ";
         }

         private void btnis_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = "is ";
         }

         private void btncharacter_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = "'' ";
         }

         private void btnempty_Click(object sender, EventArgs e)
         {
             this.textBoxSql.Text = "";
         }

         private void btnunequal_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = "!= ";
         }

         private void btnlike_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = "like ";
         }

         private void btnmore_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = "> ";
         }

         private void btnmoe_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = ">= ";
         }

         private void btnloe_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = "<= ";
         }

         private void btnor_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = " or ";
         }

         private void btnnull_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = "Null ";
         }

         private void btnless_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = "< ";
         }

         private void btnnot_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = " Not ";
         }

         private void btnand_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = " And ";
         }

         private void btnin_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = " In ";
         }

         private void btnunderline_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = "_";
         }

         private void btnpercent_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = "% ";
         }

         private void btnbetween_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = " Between ";
         }

         private void btnspace_Click(object sender, EventArgs e)
         {
             textBoxSql.SelectedText = " ";
         }

最后对按钮“查找”和“取消”添加点击响应函数，代码如下：

         private void button1_Click(object sender, EventArgs e)
         {
             try
             {
                 mMapControl.Map.ClearSelection(); //清除上次查询结果
                 IActiveView pActiveView = mMapControl.Map as IActiveView;
                 //pQueryFilter的实例化
                 IQueryFilter pQueryFilter = new QueryFilterClass();
                 //设置查询过滤条件
                 pQueryFilter.WhereClause = textBoxSql.Text;
                 //search的参数第一个为过滤条件，第二个为是否重复执行
                 IFeatureCursor pFeatureCursor = mFeatureLayer.Search(pQueryFilter, false);
                 //获取查询到的要素
                 IFeature pFeature = pFeatureCursor.NextFeature();
                 //判断是否获取到要素
                 while (pFeature != null)
                 {
                     mMapControl.Map.SelectFeature(mFeatureLayer, pFeature); //选择要素
                     pFeature = pFeatureCursor.NextFeature();
                 }
                 pActiveView.PartialRefresh(esriViewDrawPhase.esriViewGeoSelection, null, null);
                 pActiveView.Refresh();//刷新图层
             }
             catch (Exception ex)
             {
                 MessageBox.Show(ex.Message);
             }

         }

         private void button2_Click(object sender, EventArgs e)
         {
             this.Hide();
         }

到此为止，所有属性查询的工作已经完成，使用效果如下图所示：

如果需要清除所选要素，则添加按钮，并在其点击响应函数中添加如下代码即可：

         //清空查询
         private void barButtonItem14_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
         {
             axMapControl1.Map.ClearSelection();
             axMapControl1.Refresh();
         }