PIE屬性表多欄位的文本繪製

　　最近研究了PIE SDK文本元素的繪製相關內容，因為在我們的開發中，希望可以做到在打開一個Shp文件後，讀取到屬性表的所有欄位，然後可以選擇一些需要的欄位，將這些欄位的所有要素值的文本，繪製到shp圖中相應的要素位置上。

　　我主要是通過PIE的官方博文（https://www.cnblogs.com/PIESat/p/10172166.html）進行學習的，併在技術員姐姐的幫助下，最後成功的將文本繪製於圖上。

結果如下圖所示：

　　先打開一張屬性表欄位不為空Shp文件

　　讀取shp的屬性表中的所有欄位，選取需要繪製在圖上的欄位

　　將所選的欄位的值繪製到相應的要素的位置上

　　開發環境：vs2013 framework4

代碼如下：

　　在子視窗的構造函數中，遍歷當前shp文件屬性表的所有欄位，並設置預設好預設字體樣式

 1  #region 構造函數
 2         public FeaturesShow(IFeatureDataset featureDataset)
 3         {
 4             InitializeComponent();
 5             m_featureDataset = featureDataset;
 6             IFeature feature = m_featureDataset.GetNextFeature();
 7             for (int i = 1; i < feature.GetFieldCount(); i++)
 8             {
 9                 string fieldname = feature.GetFieldName(i);
10                 this.listBox1.Items.Add(fieldname);
11             }
12             //預設字體
13             FontDlg.Font = new Font("Calibri", 15, FontStyle.Bold);
14             FontDlg.Color = Color.Chartreuse;
15         }
16    #endregion

　　點擊了子窗體的確定後，返回得到已選擇的欄位名，和設置的字體樣式，併在圖上進行繪製

 1         private void 文本繪製ToolStripMenuItem_Click(object sender, EventArgs e)
 2         {
 3             if (mapControl1.ActiveView.CurrentLayer == null)
 4                 return;
 5             IFeatureLayer featurelayer = mapControl1.ActiveView.CurrentLayer as IFeatureLayer;
 6             if (featurelayer == null)
 7                 return;
 8 
 9             //清除圖上已繪製的元素
10             mapControl1.ActiveView.GraphicsContainer.DeleteAllElements();
11             //獲得要讀取的數據，傳入子窗體
12             IFeatureDataset featureDataset = featurelayer.FeatureClass.GetFeatureDataset();
13             FeaturesShow frm = new FeaturesShow(featureDataset);
14             frm.ShowDialog();       //通過視窗來選擇需要展示在圖上的特征值
15             if (frm.DialogResult == DialogResult.OK)
16             {
17                 //符號設置
18                 FontDialog m_FontDlg = frm.m_FontDlg;
19                 ITextSymbol textSymbol = new TextSymbol();                
20                 textSymbol.Color = m_FontDlg.Color;
21                 textSymbol.Font = m_FontDlg.Font;
22                 textSymbol.Size = m_FontDlg.Font.Size;              
23                
24                 int m_FeatureCount = frm.m_FeatureCount;
25                 string[] m_Fieldname=frm.m_Fieldname;
26                 int[] index = new int[m_FeatureCount+1];               
27                 IFields fields = featureDataset.GetFields();
28                 index[0] = 0;
29                 for (int i = 1; i < m_FeatureCount+1;i++ )
30                 {
31                     index[i] = fields.GetFieldIndex(m_Fieldname[i-1]);
32                 }                                        
33                 IFeature feature = featureDataset.GetFeature(0);
34                 while (feature != null)
35                 {
36                     ////取左上角坐標值
37                     IPolygon polygon = new PIE.Geometry.Polygon();
38                     polygon = feature.Geometry as IPolygon;
39                     IPointCollection poly = polygon as IPointCollection;
40                     IPoint point = poly.GetPoint(0);
41                     //創建文本元素實例對象
42                     ITextElement textElement = new PIE.Carto.TextElement();
43                     textElement.Geometry = point as IGeometry;
44                     textElement.Symbol = textSymbol;
45                     
46                     for(int i=1;i<m_FeatureCount+1;i++)
47                     {
48                         string strValue = "";
49                         if (feature.IsValueNull(index[i]) == false)
50                         {
51                             strValue = m_Fieldname[i-1] + ":" + feature.GetValue(index[i]).ToString() + "\r\n";                                
52                             textElement.Text = textElement.Text+strValue;                                                                
53                         }                                
54                     }
55                     if(textElement.Text!="")
56                     {
57                         string strID = fields.GetFieldName(0) + ":" + feature.GetValue(index[0]).ToString() + "\r\n";
58                         textElement.Text = strID + textElement.Text;
59                         mapControl1.ActiveView.GraphicsContainer.AddElement(textElement);
60                     }
61                     feature = featureDataset.GetNextFeature();                                      
62                 }
63                 mapControl1.PartialRefresh(ViewDrawPhaseType.ViewAll);
64             }
65         }

有幫助的話，記得點個贊支持一下哦~
也歡迎各位評論，指點，交流