此功能是通过点击主窗体上的SQL查询按钮http://s12/middle/694deb73ha5968b21c61b&690SQL属性查询" TITLE="AE+C# SQL属性查询" />，触发其点击事件，函数如下所示

           //判断是否已经打开了地图
            pMap = axMapControl1.Map;
            if (pMap.LayerCount < 1)
            {
                MessageBox.Show("请先加载图层！");
                return;
            }
            //创建一个SelectLayer类来控制选择图层查询
            SelectLayer lSelectLayer = new SelectLayer(axMapControl1);
            //打开查询对话框
            lSelectLayer.ShowDialog();

    SelectLayer类是一个窗体类，其样式如下

http://s9/middle/694deb73ha59691c6eb58&690SQL属性查询" TITLE="AE+C# SQL属性查询" />

    SelectLayer类代码如下：

using System;
using System.Data;
using System.Windows.Forms;
using System.IO;
using ESRI.ArcGIS.DataSourcesFile;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.MapControl;
using ESRI.ArcGIS.Geometry;
using ESRI.ArcGIS.DataSourcesRaster;
using ESRI.ArcGIS.CartoUI;
using DevComponents.DotNetBar;
using System.Collections;

namespace linxiangtu
{
    public partial class SelectLayer : Office2007Form
    {
        public SelectLayer(AxMapControl lAxMapControl)
        {
            InitializeComponent();

            //传入可供查询的地图
            this.pAxMapControl = lAxMapControl;

            //将所有图层名添加进comboBoxLayer，并设置默认值为第一项
            for (int i = 0; i < pAxMapControl .LayerCount ; i++)
            {
                comboBoxLayer.Items.Add(pAxMapControl .get_Layer (i).Name );
            }
            comboBoxLayer.SelectedIndex = 0;

            //设置comboBoxMethod的选择项，并设置默认值为第一项
            comboBoxMethod.Items.Add("新建选择集");
            comboBoxMethod.Items.Add("添加进已有的选择集");
            comboBoxMethod.Items.Add("从当前选择集中清除");
            comboBoxMethod.Items.Add("从当前选择集中再次筛选");
            comboBoxMethod.SelectedIndex = 0;

            //最初时获取唯一值框不可使用
            listBox_Value.Visible = false;
        }

        //全局变量pAxMapControl

        private AxMapControl pAxMapControl;

        #region SymbolButton 运算符点击事件
        private void button_equal_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " =";
        }

        private void button_Notequal_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " <>";
        }

        private void button_Big_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " >";
        }

        private void button_BigEqual_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " >=";
        }

        private void button_Small_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " <";
        }

        private void button_Smallequal_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " <=";
        }

        private void button_Brace_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " ()";
        }

        private void button_Like_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " LIKE";
        }

        private void button_And_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " AND";
        }

        private void button_Or_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " OR";
        }

        private void button_Not_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " NOT";
        }

        private void button_IS_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " IS";
        }

        private void button_Clear_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text = "";
        }

        private void button_What_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " ?";
        }

        private void button_All_Click(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " *";
        }
        #endregion

        private void comboBoxLayer_SelectedValueChanged(object sender, EventArgs e)
        {
            //如果没有图层被选择，将不能添加字段
            if (comboBoxLayer.Text != null)
            {
                //清空listBox_Field
                listBox_Field.Items.Clear();

                //获取要素
                IFeatureLayer lFeatureLayer = (IFeatureLayer)pAxMapControl.Map.get_Layer(comboBoxLayer.SelectedIndex);
                IFeatureCursor lFeatureCursor = lFeatureLayer.Search(null, true);
                IFeature lFeature = lFeatureCursor.NextFeature();

                //循环添加所属图层的字段名进入listBox_Field中
                //对于esriFieldTypeGeometry类型的自动则不予以添加
                for (int i = 0; i < lFeature.Fields.FieldCount; i++)
                {
                    if (lFeature.Fields.get_Field(i).Type != esriFieldType.esriFieldTypeGeometry)
                    {
                        listBox_Field.Items.Add(lFeature.Fields.get_Field(i).Name);
                    }  
                }

                //设置当前选择字段为第一个
                listBox_Field.SelectedIndex = 0;
                //将描述信息修改
                label_Description.Text = "SELECT * FROM " + comboBoxLayer.Text + " WHERE:";
            }
        }

        //双击选中字段，将其添加进条件框
        private void listBox_Field_DoubleClick(object sender, EventArgs e)
        {
            IFeatureLayer lFeatureLayer = (IFeatureLayer)pAxMapControl.Map.get_Layer(comboBoxLayer.SelectedIndex);
            if (lFeatureLayer.DataSourceType == "Shapefile Feature Class")//shapefile文件
            {
                textBox_WhereClause.Text += " "" + listBox_Field.Text + "" ";
            }
            else
            {
                textBox_WhereClause.Text += " [" + listBox_Field.Text + "] ";
            }
        }

        //双击选中值，将其添加进条件框
        private void listBox_Value_DoubleClick(object sender, EventArgs e)
        {
            textBox_WhereClause.Text += " " + listBox_Value.Text ;
        }

        //当选择另一个字段时，将List_Value框隐藏
        private void listBox_Field_SelectedIndexChanged(object sender, EventArgs e)
        {
            listBox_Value.Visible = false;
            button_GetValue.Enabled = true;
        }

        //应用按钮
        private void button_Apply_Click_1(object sender, EventArgs e)
        {
            if (textBox_WhereClause.Text != "")
            {
                try
                {
                    IFeatureLayer lFeatureLayer = (IFeatureLayer)pAxMapControl.get_Layer(comboBoxLayer.SelectedIndex);
                    IFeatureSelection lFeatureSelection = (IFeatureSelection)lFeatureLayer;

                    //判断选择的SQL方法的类型
                    esriSelectionResultEnum lesriSREnum = esriSelectionResultEnum.esriSelectionResultNew;
                    switch (comboBoxMethod.SelectedIndex)
                    {
                        case 0:
                            lesriSREnum = esriSelectionResultEnum.esriSelectionResultNew;
                            break;
                        case 1:
                            lesriSREnum = esriSelectionResultEnum.esriSelectionResultAdd;
                            break;
                        case 2:
                            lesriSREnum = esriSelectionResultEnum.esriSelectionResultSubtract;
                            break;
                        case 3:
                            lesriSREnum = esriSelectionResultEnum.esriSelectionResultAnd;
                            break;
                        default:
                            MessageBox.Show("请选择一种查询方法");
                            break;
                    }

                    //创建查询的条件
                    IQueryFilter2 lQueryFilter = new QueryFilterClass();
                    lQueryFilter.WhereClause = textBox_WhereClause.Text;

                    //根据查询添加进行选择，并刷新屏幕
                    lFeatureSelection.SelectFeatures(lQueryFilter, lesriSREnum, false);
                    pAxMapControl.ActiveView.Refresh();
                }
                catch (Exception)
                {
                    MessageBox.Show("输入的SQL查询不符合语法要求");
                }
            }
            else
            {

                MessageBox.Show("请选择需要查询的图层");

            }
        }

        //取消按钮
        private void button_Cancel_Click_1(object sender, EventArgs e)
        {
            this.Close();
        }

        //清除按钮
        private void button_Clear_Click_1(object sender, EventArgs e)
        {
            textBox_WhereClause.Clear();
           
        }

        //获取唯一值按钮
        private void button_GetValue_Click(object sender, EventArgs e)
        {
            //获取要素图层与要素类，将其作为参数传入GetUniqueValue()函数
            IFeatureLayer lFeatureLayer = (IFeatureLayer)pAxMapControl.get_Layer(comboBoxLayer.SelectedIndex);
            IFeatureClass lFeatureClass = lFeatureLayer.FeatureClass;

            //将返回的所有值存入allValue数组中,并进行排序
            string[] allValue = GetUniqueValue(lFeatureClass ,listBox_Field.Text);
            Array.Sort(allValue);

            //获取字段对象，用于在将其值添加进listbox_value中时判断字段类型
            IFeatureCursor lFeatureCursor = lFeatureLayer.Search(null, true);
            IFeature lFeature = lFeatureCursor.NextFeature();
            IField lField=new FieldClass();
            for (int j = 0; j < lFeature.Fields.FieldCount; j++)
            {
                if (listBox_Field.Text == lFeature.Fields.get_Field(j).Name)
                {
                    lField = lFeature.Fields.get_Field(j);
                }
            }
            //将之前listBox_Value中的值清空，然后添加此次选中字段的所有数据
            listBox_Value.Items.Clear();
            for (int i = 0; i < allValue.Length; i++)
            {
                if (lField.Type==esriFieldType.esriFieldTypeString)
                {
                    allValue[i]="\'" + allValue[i] + "\'";
                    listBox_Value.Items.Add(allValue[i]);
                }
                else
                {
                    listBox_Value.Items.Add(allValue[i]);
                }
            }
            listBox_Value.Visible = true;
            button_GetValue.Enabled = false;
        }

         /// <summary>
         /// 得到要素类某字段的唯一值
         /// </summary>
         /// <param name="pFeatureClass">要素类</param>
         /// <param name="strFld">指定要得到唯一值的字段</param>
         /// <returns>唯一值字符数据</returns>
         public string[] GetUniqueValue(IFeatureClass pFeatureClass,string strFld)
         {
             //得到IFeatureCursor游标
            IFeatureCursor pCursor=pFeatureClass.Search(null,false);

            //IDataStatistics对象实例生成
            IDataStatistics pData=new DataStatisticsClass();
            pData.Field=strFld;
            pData.Cursor=pCursor as ICursor;

            //枚举唯一值
            IEnumerator pEnumVar=pData.UniqueValues ;

            //记录总数
            int RecordCount=pData.UniqueValueCount;

            //字符数组
            string[] strValue=new string[RecordCount]; 
            pEnumVar.Reset();
      
            int i=0;

            while(pEnumVar.MoveNext())
            {
                strValue[i++]=pEnumVar.Current.ToString();
            }          

            return strValue;
         }
        
       

      
    }
}