c# 动态lambda实现二级过滤（支持多种参数类型和模糊查询）

效果

调用方法

实体类（可以根据需求更换）

public class ToolStr50
{public bool isSelected { get; set; }public string toolStr1 { get; set; }public string toolStr2 { get; set; }public string toolStr3 { get; set; }public string toolStr4 { get; set; }public string toolStr5 { get; set; }public string toolStr6 { get; set; }public string toolStr7 { get; set; }public string toolStr8 { get; set; }public string toolStr9 { get; set; }public string toolStr10 { get; set; }public int toolInt1 { get; set; }public int toolInt2 { get; set; }public int toolInt3 { get; set; }public int toolInt4 { get; set; }public int toolInt5 { get; set; }public int toolInt6 { get; set; }public int toolInt7 { get; set; }public int toolInt8 { get; set; }public int toolInt9 { get; set; }public int toolInt10 { get; set; }public double toolDouble1 { get; set; }public double toolDouble2 { get; set; }public double toolDouble3 { get; set; }public double toolDouble4 { get; set; }public double toolDouble5 { get; set; }public double toolDouble6 { get; set; }public double toolDouble7 { get; set; }public double toolDouble8 { get; set; }public double toolDouble9 { get; set; }public double toolDouble10 { get; set; }public DateTime toolDate1 { get; set; }public DateTime toolDate2 { get; set; }public DateTime toolDate3 { get; set; }public DateTime toolDate4 { get; set; }public DateTime toolDate5 { get; set; }public DateTime toolDate6 { get; set; }public DateTime toolDate7 { get; set; }public DateTime toolDate8 { get; set; }public DateTime toolDate9 { get; set; }public DateTime toolDate10 { get; set; }
}

传入需要二级过滤的数据

 public void ShowSecondaryFiltration(){var columnMappings = new Dictionary<string, string>{{ "采购日期", "toolStr26" },{ "采购周期", "toolInt10" },{ "采购回复交期", "toolStr31" },{ "采购说明", "toolStr53" },{ "生产订单号", "toolStr1" },{ "来源单号", "toolStr2" },{ "采购订单号", "toolStr3" },{ "行号", "toolInt1" },{ "料号", "toolStr4" },{ "品名", "toolStr5" },{ "规格描述", "toolStr6" },{ "现存量", "toolInt2" },{ "单位", "toolStr11" },{ "采购数量(计量)", "toolInt3" },{ "收货数量(计量)", "toolInt4" },{ "已退货数(计量)", "toolInt5" },{ "实际入库数(计量)", "toolInt6" },{ "入库单号", "toolStr16" },{ "已暂收数量(计量)", "toolInt7" },{ "最后交货日期", "toolStr18" },{ "逾期天数(负数未到期)", "toolInt8" },{ "品质异常报告日期", "toolStr19" },{ "品质问题描述", "toolStr20" },{ "处理结论", "toolStr21" },{ "未交数量(计量)", "toolInt9" },{ "交货结案日期", "toolStr23" },{ "请购日期", "toolStr24" },{ "PMC交单日期", "toolStr25" },{ "理论交期", "toolStr28" },{ "要求交期", "toolStr29" },{ "订单回传日期", "toolStr30" },{ "色板_模板_图纸提供情况", "toolStr32" },{ "异常反馈", "toolStr33" },{ "预付款比例", "toolInt11" },{ "预付款支付日期", "toolStr35" },{ "尾款比例", "toolInt12" },{ "尾款支付日期", "toolStr39" },{ "采购员", "toolStr44" },{ "请购制单人", "toolStr40" },{ "供应商名称", "toolStr46" },{ "请购单备注", "toolStr42" },{ "采购单备注", "toolStr45" },{ "可用量", "toolStr8" },{ "含税单价", "toolDouble1" },{ "含税金额", "toolDouble2" },{ "采购到货日期", "toolStr37" },{ "财务交单日期", "toolStr38" },{ "请购人", "toolStr41" },{ "采购制单人", "toolStr43" },{ "采购订单结案状态", "toolStr48" },{ "修改日期_请购", "toolStr50" },{ "修改日期_采购", "toolStr51" },{ "PMC要求交货日期", "toolStr52" }};var traceWindow = new TraceTableSecondaryFiltration(columnMappings, OdlIbo);traceWindow.QueryConditions = _queryConditions;if (traceWindow.ShowDialog() == true) // 检查对话框的结果{var filteredIbo = traceWindow.FilteredData;_queryConditions = traceWindow.QueryConditions;Ibo = filteredIbo;// 使用 filteredIbo 进行后续处理}if (_queryConditions.Count == 0){SelectInfo();}//更新总条数和总金额InfoCount = "数据汇总:" + Ibo.Count.ToString() + "条";decimal total = Ibo.Sum(x => Convert.ToDecimal(x.toolStr10)); // 假设 TaxInclusiveSum 是 double 类型  total = decimal.Round(total, 4);//TaxinclusiveSum = "合计含税金额:" + total.ToString();}

窗体页面TraceTableSecondaryFiltration.xaml

<Window x:Class="GMWPF.Views.ModuleMenu.Purchase.PurchaseModle1.ChildWindow.TraceTableSecondaryFiltration"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:d="http://schemas.microsoft.com/expression/blend/2008"xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"xmlns:local="clr-namespace:GMWPF.Views.ModuleMenu.Purchase.PurchaseModle1.ChildWindow"mc:Ignorable="d"Title="TraceTableSecondaryFiltration" Height="450" Width="800"WindowStartupLocation="CenterScreen"><Grid Margin="10" Name="myDynamicGrid"><Grid.RowDefinitions><RowDefinition Height="Auto"/><RowDefinition Height="Auto"/><RowDefinition Height="Auto"/><RowDefinition Height="Auto"/><RowDefinition Height="Auto"/><RowDefinition Height="*"/><!-- 让表格占用剩余空间 --></Grid.RowDefinitions><TextBlock Text="字段名称" Margin="49,34,655,0" VerticalAlignment="Top" Grid.Row="0"/><!-- <ComboBox Name="FieldNameComboBox" Margin="25,5,640,0" VerticalAlignment="Top" ItemsSource="{Binding FieldNames}" SelectedItem="{Binding SelectedFieldName, Mode=TwoWay}" SelectionChanged="FieldNameComboBox_SelectionChanged"Grid.Row="1"/>--><ComboBox Name="FieldNameComboBox" Margin="25,5,640,0" VerticalAlignment="Top" IsEditable="True"IsTextSearchEnabled="False"PreviewTextInput="FieldNameComboBox_PreviewTextInput"ItemsSource="{Binding FieldNames}" SelectedItem="{Binding SelectedFieldName, Mode=TwoWay}" SelectionChanged="FieldNameComboBox_SelectionChanged"Grid.Row="1"/><TextBlock Text="条件" Margin="227,34,495,0" VerticalAlignment="Top" Grid.Row="0"/><ComboBox Name="ConditionComboBox" Margin="184,5,471,0" VerticalAlignment="Top" ItemsSource="{Binding Conditions}" SelectedItem="{Binding SelectedCondition}" Grid.Row="1"/><TextBlock Text="条件值" Margin="402,34,320,0" VerticalAlignment="Top" Grid.Row="0"/><!-- <ComboBox Name="ValueComboBox" Margin="357,5,275,0" VerticalAlignment="Top" ItemsSource="{Binding ConditionValues}" SelectedItem="{Binding SelectedConditionValue}" Grid.Row="1"/>--><ComboBox Name="ValueComboBox" Margin="357,5,275,0" VerticalAlignment="Top" IsEditable="True"IsTextSearchEnabled="False"Text="{Binding InputValue, Mode=TwoWay}"PreviewTextInput="ConditionComboBox_PreviewTextInput"SelectionChanged="ConditionComboBox_SelectionChanged"ItemsSource="{Binding ConditionValues}" SelectedItem="{Binding SelectedConditionValue}" Grid.Row="1"/><TextBlock Text="关系" Margin="564,34,168,0" VerticalAlignment="Top" Grid.Row="0"/><ComboBox Name="RelationComboBox" Margin="532,5,154,0" VerticalAlignment="Top" ItemsSource="{Binding RelationValues}" SelectedItem="{Binding SelectedRelationValue}" SelectionChanged="RelationComboBox_SelectionChanged"Grid.Row="1"/><Button Content="添加" Command="{Binding AddQueryConditionCommand}" Margin="637,5,0,0" HorizontalAlignment="Left" VerticalAlignment="Top" Height="27" Grid.Row="1"/><Button Content="查询" Command="{Binding QueryCommand}" Margin="697,5,0,0" HorizontalAlignment="Left" VerticalAlignment="Top" Height="27" Grid.Row="1"/><DataGrid Name="ConditionDataGrid" Grid.Row="2" Margin="10,10,10,0" BorderThickness="1"Height="300"AutoGenerateColumns="False" ItemsSource="{Binding QueryConditions}"><DataGrid.Columns><!-- <DataGridTemplateColumn Width="200" Header="字段名称"><DataGridTemplateColumn.CellTemplate><DataTemplate><ComboBox Name="FieldNameComboBox" Margin="25,5,640,0" VerticalAlignment="Top" ItemsSource="{Binding FieldNames}" SelectedItem="{Binding SelectedFieldName}" SelectionChanged="FieldNameComboBox_SelectionChanged"Grid.Row="1"/></DataTemplate></DataGridTemplateColumn.CellTemplate><DataGridTemplateColumn.HeaderStyle><Style TargetType="DataGridColumnHeader"><Setter Property="HorizontalContentAlignment" Value="Center"/></Style></DataGridTemplateColumn.HeaderStyle></DataGridTemplateColumn>--><DataGridTextColumn Width="200" Header="字段名称" Binding="{Binding FieldName}"><DataGridTextColumn.ElementStyle><Style TargetType="TextBlock"><Setter Property="HorizontalAlignment" Value="Center"/><Setter Property="VerticalAlignment" Value="Center"/></Style></DataGridTextColumn.ElementStyle><DataGridTextColumn.HeaderStyle><Style TargetType="DataGridColumnHeader"><Setter Property="HorizontalContentAlignment" Value="Center"/></Style></DataGridTextColumn.HeaderStyle></DataGridTextColumn><DataGridTextColumn Width="100" Header="条件" Binding="{Binding Condition}"><DataGridTextColumn.ElementStyle><Style TargetType="TextBlock"><Setter Property="HorizontalAlignment" Value="Center"/><Setter Property="VerticalAlignment" Value="Center"/></Style></DataGridTextColumn.ElementStyle><DataGridTextColumn.HeaderStyle><Style TargetType="DataGridColumnHeader"><Setter Property="HorizontalContentAlignment" Value="Center"/></Style></DataGridTextColumn.HeaderStyle></DataGridTextColumn><DataGridTextColumn Width="200" Header="条件值" Binding="{Binding ConditionValue}"><DataGridTextColumn.ElementStyle><Style TargetType="TextBlock"><Setter Property="HorizontalAlignment" Value="Center"/><Setter Property="VerticalAlignment" Value="Center"/></Style></DataGridTextColumn.ElementStyle><DataGridTextColumn.HeaderStyle><Style TargetType="DataGridColumnHeader"><Setter Property="HorizontalContentAlignment" Value="Center"/></Style></DataGridTextColumn.HeaderStyle></DataGridTextColumn><DataGridTextColumn Width="100" Header="关系" Binding="{Binding RelationValue}"><DataGridTextColumn.ElementStyle><Style TargetType="TextBlock"><Setter Property="HorizontalAlignment" Value="Center"/><Setter Property="VerticalAlignment" Value="Center"/></Style></DataGridTextColumn.ElementStyle><DataGridTextColumn.HeaderStyle><Style TargetType="DataGridColumnHeader"><Setter Property="HorizontalContentAlignment" Value="Center"/></Style></DataGridTextColumn.HeaderStyle></DataGridTextColumn><DataGridTemplateColumn Width="200" Header="操作"><DataGridTemplateColumn.CellTemplate><DataTemplate><Button Content="删除" Width="80" Command="{Binding DataContext.DeleteConditionCommand, RelativeSource={RelativeSource AncestorType={x:Type Window}}}"CommandParameter="{Binding}"/></DataTemplate></DataGridTemplateColumn.CellTemplate><DataGridTemplateColumn.HeaderStyle><Style TargetType="DataGridColumnHeader"><Setter Property="HorizontalContentAlignment" Value="Center"/></Style></DataGridTemplateColumn.HeaderStyle></DataGridTemplateColumn></DataGrid.Columns></DataGrid></Grid>
</Window>

窗体实现类TraceTableSecondaryFiltration.xaml.cs

这里在进行数据对比时对数据进行了类型转换，因为string类型的对比会出现

“4”>“20”的情况

using CommunityToolkit.Mvvm.Input;
using SQLSugarDB.Model.Public;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Input;
using Expression = System.Linq.Expressions.Expression;
namespace GMWPF.Views.ModuleMenu.Purchase.PurchaseModle1.ChildWindow
{public partial class TraceTableSecondaryFiltration : Window, INotifyPropertyChanged{public List<ToolStr50> FilteredData { get; private set; }private string _inputValue;//条件值下拉框中手动输入的值public string InputValue{get { return _inputValue; }set{if (_inputValue != value){_inputValue = value;OnPropertyChanged(nameof(InputValue));}}}private Dictionary<string, string> _columnMappings;//所有的列和对应Toolstr属性的映射关系private List<ToolStr50> _Ibo;//所有的数据private List<string> _fieldNames = new List<string>(); // 字段名public List<string> FieldNames{get { return _fieldNames; }set{_fieldNames = value;OnPropertyChanged(nameof(FieldNames));}}private string _selectedFieldName;public string SelectedFieldName{get { return _selectedFieldName; }set{_selectedFieldName = value;}}private ObservableCollection<string> _conditions = new ObservableCollection<string>(); // 条件public ObservableCollection<string> Conditions{get { return _conditions; }set{_conditions = value;OnPropertyChanged(nameof(Conditions));}}private string _selectedCondition;public string SelectedCondition{get { return _selectedCondition; }set{_selectedCondition = value;}}private ObservableCollection<string> _conditionValues = new ObservableCollection<string>(); // 条件值public ObservableCollection<string> ConditionValues{get { return _conditionValues; }set{_conditionValues = value;OnPropertyChanged(nameof(ConditionValues)); // 通知 UI 更新}}private string _selectedConditionValue;public string SelectedConditionValue{get { return _selectedConditionValue; }set{_selectedConditionValue = value;}}private ObservableCollection<string> _relationValues = new ObservableCollection<string>(); // 关系public ObservableCollection<string> RelationValues{get { return _relationValues; }set{_relationValues = value;}}private string _selectedRelationValue;public string SelectedRelationValue{get { return _selectedRelationValue; }set{_selectedRelationValue = value;}}private ObservableCollection<SecondQueryCondition> _queryConditions = new ObservableCollection<SecondQueryCondition>();public event PropertyChangedEventHandler PropertyChanged;public ObservableCollection<SecondQueryCondition> QueryConditions{get => _queryConditions;set{_queryConditions = value;}}public List<String> FieldNamesValueBackUp;//所有字段名 备份原始数据public ObservableCollection<String> ConditionValueBackUp;//字段名对应的数据 备份原始数据public TraceTableSecondaryFiltration(Dictionary<string, string> columnMappings, List<ToolStr50> Ibo){_columnMappings = columnMappings;_Ibo = Ibo;InitializeComponent();DataContext = this; // 设置数据上下文为当前窗口//将columnMappings所有的key拿出来放进List<string> _fieldNames中_fieldNames = new List<string>(_columnMappings.Keys);FieldNamesValueBackUp = _fieldNames;Conditions.Add("大于");Conditions.Add("大于等于");Conditions.Add("小于");Conditions.Add("小于等于");Conditions.Add("等于");Conditions.Add("不等于");Conditions.Add("包含");RelationValues.Add("并且");RelationValues.Add("或者");//给所有的下拉框的值备份起来//设定个默认值//SelectedRelationValue = "并且";}private void ConditionComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e){// 当用户选择了已有的项时，更新 InputValue 为所选项的值if (ValueComboBox.SelectedItem != null){InputValue = ValueComboBox.SelectedItem.ToString();}else{// 如果没有选中任何项，保持 Text 的自定义输入InputValue = ValueComboBox.Text;}}//监听下拉框输入数据进行模糊查询private void ConditionComboBox_PreviewTextInput(object sender, TextCompositionEventArgs e){var comboBox = sender as ComboBox;var view = (CollectionView)CollectionViewSource.GetDefaultView(comboBox.ItemsSource);if (view != null){string text = comboBox.Text;if (string.IsNullOrEmpty(text)){ConditionValues = ConditionValueBackUp;_conditionValues = ConditionValueBackUp;}else{ConditionValues = new ObservableCollection<string>(ConditionValueBackUp.Where(p => p.Contains(text)));//ConditionValues = ConditionValueBackUp.Where(p => p.Contains(text)).ToList();}}}//监听下拉框输入数据进行模糊查询private void FieldNameComboBox_PreviewTextInput(object sender, TextCompositionEventArgs e){var comboBox = sender as ComboBox;var view = (CollectionView)CollectionViewSource.GetDefaultView(comboBox.ItemsSource);if (view != null){string text = comboBox.Text;if (string.IsNullOrEmpty(text)){FieldNames = FieldNamesValueBackUp;_fieldNames = FieldNamesValueBackUp;}else{FieldNames = FieldNamesValueBackUp.Where(p => p.Contains(text)).ToList();}}}// 处理 ComboBox 的 SelectionChanged 事件private void RelationComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e){try {// 获取选中的项string selectedValue = RelationComboBox.SelectedItem as string;// 如果选中的值不为空，进行操作// 如果其他属性有空值则不清空if (!string.IsNullOrEmpty(selectedValue)&& !(string.IsNullOrEmpty(_selectedFieldName) ||string.IsNullOrEmpty(_selectedCondition) ||string.IsNullOrEmpty(_selectedConditionValue) ||string.IsNullOrEmpty(_selectedRelationValue))){AddQueryCondition();//添加到查询条件列表中}}catch(Exception ex){MessageBox.Show(ex.Message);}}[RelayCommand]public void AddQueryCondition(){try {// 检查是否有空值或空字符串if (string.IsNullOrEmpty(_selectedFieldName) ||string.IsNullOrEmpty(_selectedCondition) ||string.IsNullOrEmpty(_selectedRelationValue) ||(string.IsNullOrEmpty(_selectedConditionValue) &&string.IsNullOrEmpty(InputValue))){return; // 如果有空值，直接返回}// 创建并添加 SecondQueryCondition 对象到 QueryConditions 列表QueryConditions.Add(new SecondQueryCondition(QueryConditions.Count + 1, _selectedFieldName, _selectedCondition, string.IsNullOrEmpty(_selectedConditionValue)?InputValue: _selectedConditionValue, _selectedRelationValue));//清空查询条件RelationComboBox.SelectedItem = null; // 清空 ComboBox 的选中项ValueComboBox.SelectedItem = null;ConditionComboBox.SelectedItem = null;FieldNameComboBox.SelectedItem = null;}catch(Exception ex){MessageBox.Show(ex.Message);}}private void FieldNameComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e){try {ConditionValues.Clear();_columnMappings.TryGetValue(_selectedFieldName, out string property);if (_Ibo == null){return;}foreach (var item in _Ibo){string propertyValue = item.GetType().GetProperty(property)?.GetValue(item)?.ToString();if (!string.IsNullOrEmpty(propertyValue) && !ConditionValues.Contains(propertyValue)){ConditionValues.Add(propertyValue);}}ConditionValueBackUp = ConditionValues;} catch (Exception ex){return;}}[RelayCommand]public void DeleteCondition(SecondQueryCondition secondQueryCondition){QueryConditions.Remove(secondQueryCondition);}[RelayCommand]public void Query(){var parameter = Expression.Parameter(typeof(ToolStr50), "p");Expression finalExpression = null;foreach (var queryCondition in QueryConditions){if (_columnMappings.TryGetValue(queryCondition.FieldName, out string property)){var member = Expression.Property(parameter, property);var conditionValue = Expression.Constant(queryCondition.ConditionValue, typeof(string));Expression comparison;// 尝试解析为 int, double, DateTimeif (int.TryParse(queryCondition.ConditionValue, out int intValue)){var intMember = Expression.Convert(member, typeof(int));var intConditionValue = Expression.Constant(intValue, typeof(int));comparison = GetIntegerComparison(queryCondition.Condition, intMember, intConditionValue);}else if (double.TryParse(queryCondition.ConditionValue, out double doubleValue)){var doubleMember = Expression.Convert(member, typeof(double));var doubleConditionValue = Expression.Constant(doubleValue, typeof(double));comparison = GetDoubleComparison(queryCondition.Condition, doubleMember, doubleConditionValue);}//如果日期类型无法对比直接注释掉，按照string类型对比//else if (DateTime.TryParse(queryCondition.ConditionValue, out DateTime dateTimeValue))//{//    var dateTimeMember = Expression.Convert(member, typeof(DateTime));//    var dateTimeConditionValue = Expression.Constant(dateTimeValue, typeof(DateTime));//    comparison = GetDateTimeComparison(queryCondition.Condition, dateTimeMember, dateTimeConditionValue);//}else{// 如果无法转换，继续使用字符串比较comparison = GetStringComparison(queryCondition.Condition, member, conditionValue);}// 组合条件if (finalExpression == null){finalExpression = comparison;}else{if (queryCondition.RelationValue.Equals("并且")){finalExpression = Expression.AndAlso(finalExpression, comparison); // 使用 AndAlso 组合条件}if (queryCondition.RelationValue.Equals("或者")){finalExpression = Expression.Or(finalExpression, comparison); // 使用 Or 组合条件}}}}// 生成最终的 Lambda 表达式if (finalExpression != null){var lambda = Expression.Lambda<Func<ToolStr50, bool>>(finalExpression, parameter);FilteredData = _Ibo.Where(lambda.Compile()).ToList();this.DialogResult = true; // 可选: 设置窗口的结果this.Close(); // 关闭窗口}else //没有查询条件查全部{FilteredData = _Ibo;this.DialogResult = true; // 可选: 设置窗口的结果this.Close(); // 关闭窗口}}private Expression GetIntegerComparison(string condition, Expression member, Expression conditionValue){return condition switch{"大于" => Expression.GreaterThan(member, conditionValue),"大于等于" => Expression.GreaterThanOrEqual(member, conditionValue),"小于" => Expression.LessThan(member, conditionValue),"小于等于" => Expression.LessThanOrEqual(member, conditionValue),"等于" => Expression.Equal(member, conditionValue),"不等于" => Expression.NotEqual(member, conditionValue),_ => throw new NotSupportedException($"不支持的条件: {condition}")};}private Expression GetDoubleComparison(string condition, Expression member, Expression conditionValue){return condition switch{"大于" => Expression.GreaterThan(member, conditionValue),"大于等于" => Expression.GreaterThanOrEqual(member, conditionValue),"小于" => Expression.LessThan(member, conditionValue),"小于等于" => Expression.LessThanOrEqual(member, conditionValue),"等于" => Expression.Equal(member, conditionValue),"不等于" => Expression.NotEqual(member, conditionValue),_ => throw new NotSupportedException($"不支持的条件: {condition}")};}private Expression GetDateTimeComparison(string condition, Expression member, Expression conditionValue){return condition switch{"大于" => Expression.GreaterThan(member, conditionValue),"大于等于" => Expression.GreaterThanOrEqual(member, conditionValue),"小于" => Expression.LessThan(member, conditionValue),"小于等于" => Expression.LessThanOrEqual(member, conditionValue),"等于" => Expression.Equal(member, conditionValue),"不等于" => Expression.NotEqual(member, conditionValue),_ => throw new NotSupportedException($"不支持的条件: {condition}")};}private Expression GetStringComparison(string condition, Expression member, Expression conditionValue){// 比较两个字符串时，我们需要使用 string.Compare 方法var compareMethod = typeof(string).GetMethod("Compare", new[] { typeof(string), typeof(string) });return condition switch{// 等于"等于" => Expression.Equal(member, conditionValue),// 不等于"不等于" => Expression.NotEqual(member, conditionValue),// 大于"大于" => Expression.GreaterThan(Expression.Call(null, compareMethod, member, conditionValue),Expression.Constant(0)),// 小于"小于" => Expression.LessThan(Expression.Call(null, compareMethod, member, conditionValue),Expression.Constant(0)),// 大于等于"大于等于" => Expression.GreaterThanOrEqual(Expression.Call(null, compareMethod, member, conditionValue),Expression.Constant(0)),// 小于等于"小于等于" => Expression.LessThanOrEqual(Expression.Call(null, compareMethod, member, conditionValue),Expression.Constant(0)),// 包含"包含" => Expression.Call(member,typeof(string).GetMethod("Contains", new[] { typeof(string) }),conditionValue),_ => throw new NotSupportedException($"不支持的条件: {condition}")};}// 触发属性更新通知的方法protected virtual void OnPropertyChanged(string propertyName){PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));}// 模糊查询方法public void UpdateFieldNames(string searchText){FieldNames = _fieldNames.Where(p => p.Contains(searchText)).ToList();}}
}

动态生成的lambda表达式：

模糊查询的逻辑

在下拉框输入字段后会显示服务要求的字段

代码体现

   <TextBlock Text="字段名称" Margin="49,34,655,0" VerticalAlignment="Top" Grid.Row="0"/><ComboBox Name="FieldNameComboBox" Margin="25,5,640,0" VerticalAlignment="Top" IsEditable="True"IsTextSearchEnabled="False"PreviewTextInput="FieldNameComboBox_PreviewTextInput"ItemsSource="{Binding FieldNames}" SelectedItem="{Binding SelectedFieldName, Mode=TwoWay}" SelectionChanged="FieldNameComboBox_SelectionChanged"Grid.Row="1"/>

1.IsEditable="True"控制 ComboBox 是否可以编辑。设置为 True 时，用户可以直接在 ComboBox 中输入文本；设置为 False 时，用户只能从下拉列表中选择项，而不能直接输入。2.IsTextSearchEnabled="False"控制是否启用文本搜索功能。在启用时，用户输入的文本将用来在列表项中进行搜索。如果设置为 False，则禁用此功能。3.PreviewTextInput="FieldNameComboBox_PreviewTextInput"这是 ComboBox 的事件处理器，当用户在 ComboBox 中输入文本时触发。PreviewTextInput 是一个 预处理 事件，在文本输入之前触发，可以用来在用户输入时进行拦截或处理（例如输入验证）。事件处理方法是 FieldNameComboBox_PreviewTextInput，这是在代码后面定义的一个方法，它会处理此事件。例如，可能会检查用户输入是否符合某些规则。

// 监听 ComboBox 输入事件进行模糊查询
private void FieldNameComboBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
{// 将 sender 强制转换为 ComboBox 控件var comboBox = sender as ComboBox;// 获取 ComboBox 的数据源，并转换为可操作的集合视图（CollectionView）var view = (CollectionView)CollectionViewSource.GetDefaultView(comboBox.ItemsSource);// 如果视图不为空，则进行后续处理if (view != null){// 获取 ComboBox 中当前输入的文本string text = comboBox.Text;// 如果输入文本为空，恢复备份的所有项if (string.IsNullOrEmpty(text)){// 恢复 FieldNames 为原始备份的值FieldNames = FieldNamesValueBackUp;_fieldNames = FieldNamesValueBackUp;}else{// 否则，使用输入文本进行模糊查询，筛选出包含该文本的项FieldNames = FieldNamesValueBackUp.Where(p => p.Contains(text)).ToList();}}
}