对已有IFields补充添加Field

本文介绍如何使用ArcGIS API为现有要素图层添加字段,并对比不同方法的效果。通过使用IClass::AddField方法成功实现了字段的添加。

原博客【传送门

现在需要对已有的要素图层添加字段,尝试以下代码:

IFeatureClass pFc= ((IFeatureLayer)lyrRec).FeatureClass;          
IFieldsEdit fldsE = pFc.Fields as IFieldsEdit;
IField fld = new FieldClass();
IFieldEdit2 fldE = fld as IFieldEdit2;
fldE.Type_2 = esriFieldType.esriFieldTypeString;
fldE.Name_2 = "XXX";
ic.AddField(fld);
int idTest = gpsFc.Fields.FindField("XXX");
 
调试跟踪,发现IdTest不等于-1 说明执行成功,但是再次启动发现字段未成功添加到要素集

查看帮助 ,对已存在的要素集添加字段 需要用到IClass

IFeatureClass pFc= ((IFeatureLayer)lyrRec).FeatureClass;
IClass pClass=pFc as IClass;

IFieldsEdit fldsE = pFc.Fields as IFieldsEdit;
IField fld = new FieldClass();
IFieldEdit2 fldE = fld as IFieldEdit2;
fldE.Type_2 = esriFieldType.esriFieldTypeString;
fldE.Name_2 = "XXX";
pClass.AddField(fld);

再次执行 成功!

AddField is used when creating a fields collection and cannot be used to insert a field into a fields collection belonging to an existing table. To add a field to an existing object class, use the IClass::AddField method.
意思就是说如果修改的是当前已经存在的表或者要数类的字段, 那么你就使用IClass::AddField方法生成字段
新建要素集则不会出现这种情况

 

转载于:https://www.cnblogs.com/marvelousone/p/7680257.html

using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using ESRI.ArcGIS.Carto; using ESRI.ArcGIS.Geodatabase; namespace WindowsFormsApplication1 { public partial class Form2 : Form { private Form1 mainForm; // 主窗体引用 private ILayer selectedLayer; // 当前选中的图层 public Form2(Form1 form) { InitializeComponent(); mainForm = form; } private void Form2_Load(object sender, EventArgs e) { // 初始化图层列表 LoadLayers(); } // 加载图层到下拉列表 private void LoadLayers() { cboLayers.Items.Clear(); IMap map = mainForm.axMapControl1.Map; for (int i = 0; i < map.LayerCount; i++) { ILayer layer = map.get_Layer(i); cboLayers.Items.Add(layer.Name); } if (cboLayers.Items.Count > 0) { cboLayers.SelectedIndex = 0; } } // 获取当前选中的图层 private ILayer GetSelectedLayer() { if (cboLayers.SelectedIndex < 0) return null; string layerName = cboLayers.SelectedItem.ToString(); IMap map = mainForm.axMapControl1.Map; for (int i = 0; i < map.LayerCount; i++) { if (map.get_Layer(i).Name == layerName) { return map.get_Layer(i); } } return null; } // 图层选择改变时加载字段 private void cboLayers_SelectedIndexChanged(object sender, EventArgs e) { LoadFields(); } // 加载字段到字段下拉框 private void LoadFields() { cboFields.Items.Clear(); selectedLayer = GetSelectedLayer(); if (selectedLayer == null) return; IFeatureLayer featureLayer = selectedLayer as IFeatureLayer; if (featureLayer == null) return; IFeatureClass featureClass = featureLayer.FeatureClass; IFields fields = featureClass.Fields; for (int i = 0; i < fields.FieldCount; i++) { IField field = fields.get_Field(i); cboFields.Items.Add(field.Name); } if (cboFields.Items.Count > 0) { cboFields.SelectedIndex = 0; } } // 获取唯一值 private void btnGetUniqueValues_Click(object sender, EventArgs e) { selectedLayer = GetSelectedLayer(); if (selectedLayer == null) return; IFeatureLayer featureLayer = selectedLayer as IFeatureLayer; if (featureLayer == null) { MessageBox.Show("请选择一个要素图层"); return; } IFeatureClass featureClass = featureLayer.FeatureClass; if (cboFields.SelectedIndex < 0) { MessageBox.Show("请选择字段"); return; } string fieldName = cboFields.SelectedItem.ToString(); int fieldIndex = featureClass.FindField(fieldName); if (fieldIndex == -1) { MessageBox.Show($"字段 '{fieldName}' 不存在"); return; } // 获取唯一值 IDataStatistics dataStats = new DataStatisticsClass(); dataStats.Field = fieldName; ICursor cursor = featureClass.Search(null, true); dataStats.Cursor = cursor; IEnumerator enumerator = dataStats.UniqueValues; lstValues.Items.Clear(); while (enumerator.MoveNext()) { lstValues.Items.Add(enumerator.Current.ToString()); } } // 添加到查询条件 private void btnAddToQuery_Click(object sender, EventArgs e) { if (lstValues.SelectedItem != null) { string value = lstValues.SelectedItem.ToString(); string field = cboFields.SelectedItem.ToString(); if (!string.IsNullOrEmpty(field) && !string.IsNullOrEmpty(value)) { if (txtWhereClause.Text.Length > 0) { txtWhereClause.Text += " "; } txtWhereClause.Text += $"{field} = '{value}'"; } } } // 双击列表项添加到查询条件 private void lstValues_DoubleClick(object sender, EventArgs e) { if (lstValues.SelectedItem != null) { string value = lstValues.SelectedItem.ToString(); string field = cboFields.SelectedItem.ToString(); if (!string.IsNullOrEmpty(field) && !string.IsNullOrEmpty(value)) { if (txtWhereClause.Text.Length > 0) { txtWhereClause.Text += " "; } txtWhereClause.Text += $"{field} = '{value}'"; } } } // 验证查询条件 private void btnValidate_Click(object sender, EventArgs e) { selectedLayer = GetSelectedLayer(); if (selectedLayer == null) return; IFeatureLayer featureLayer = selectedLayer as IFeatureLayer; if (featureLayer == null) { MessageBox.Show("请选择一个要素图层"); return; } string whereClause = txtWhereClause.Text.Trim(); if (string.IsNullOrEmpty(whereClause)) { MessageBox.Show("查询条件不能为空"); return; } try { IQueryFilter queryFilter = new QueryFilterClass(); queryFilter.WhereClause = whereClause; // 尝试获取一个要素来验证查询 IFeatureCursor cursor = featureLayer.FeatureClass.Search(queryFilter, false); IFeature feature = cursor.NextFeature(); if (feature != null) { MessageBox.Show("查询条件有效"); } else { MessageBox.Show("查询条件有效,但没有匹配的记录"); } } catch (Exception ex) { MessageBox.Show($"查询条件无效: {ex.Message}"); } } // 应用查询 private void btnApply_Click(object sender, EventArgs e) { selectedLayer = GetSelectedLayer(); if (selectedLayer == null) return; IFeatureLayer featureLayer = selectedLayer as IFeatureLayer; if (featureLayer == null) { MessageBox.Show("请选择一个要素图层"); return; } string whereClause = txtWhereClause.Text.Trim(); if (string.IsNullOrEmpty(whereClause)) { MessageBox.Show("查询条件不能为空"); return; } try { IQueryFilter queryFilter = new QueryFilterClass(); queryFilter.WhereClause = whereClause; // 执行查询 IFeatureCursor cursor = featureLayer.FeatureClass.Search(queryFilter, false); IFeature feature; List<int> oidList = new List<int>(); // 获取所有符合条件的OID while ((feature = cursor.NextFeature()) != null) { oidList.Add(feature.OID); } // 在Form1中高亮显示 mainForm.HighlightFeatures(selectedLayer, oidList); // 加载属性数据 LoadAttributeData(featureLayer, queryFilter); MessageBox.Show($"找到 {oidList.Count} 条记录"); } catch (Exception ex) { MessageBox.Show($"查询失败: {ex.Message}"); } } // 加载属性数据到DataGridView private void LoadAttributeData(IFeatureLayer featureLayer, IQueryFilter queryFilter) { ITable table = featureLayer.FeatureClass as ITable; if (table == null) return; DataTable dataTable = new DataTable(); IFields fields = table.Fields; // 添加列 for (int i = 0; i < fields.FieldCount; i++) { IField field = fields.get_Field(i); dataTable.Columns.Add(field.AliasName, typeof(string)); } // 查询数据 ICursor cursor = table.Search(queryFilter, false); IRow row; int maxRecords = 1000; // 限制记录数 int recordCount = 0; while ((row = cursor.NextRow()) != null && recordCount < maxRecords) { DataRow dataRow = dataTable.NewRow(); for (int i = 0; i < fields.FieldCount; i++) { object value = row.get_Value(i); dataRow[i] = value == null ? string.Empty : value.ToString(); } dataTable.Rows.Add(dataRow); recordCount++; } dgvResults.DataSource = dataTable; } // 关闭窗体 private void btnClose_Click(object sender, EventArgs e) { this.Close(); } // 清除查询条件 private void btnClear_Click(object sender, EventArgs e) { txtWhereClause.Text = ""; } // 逻辑运算符按钮点击事件 private void OperatorButton_Click(object sender, EventArgs e) { Button btn = sender as Button; if (btn != null) { if (txtWhereClause.Text.Length > 0) { txtWhereClause.Text += " "; } txtWhereClause.Text += btn.Text + " "; } } // 括号按钮点击事件 private void btnParentheses_Click(object sender, EventArgs e) { Button btn = sender as Button; if (btn != null) { if (txtWhereClause.Text.Length > 0) { txtWhereClause.Text += " "; } txtWhereClause.Text += btn.Text; } } } }不改变代码内容,仅将美元符号的字符串插值,全部替换为format方法,因为我是vs2010版本不支持美元字符串插值
最新发布
07-14
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