# Wosperry.ExpressionExtensions

**Repository Path**: wosperry/Wosperry.ExpressionExtensions

## Basic Information

- **Project Name**: Wosperry.ExpressionExtensions
- **Description**: 使用表达式树动态构建lambda表达式，减少重复的类似代码。
- **Primary Language**: C#
- **License**: Apache-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 1
- **Forks**: 0
- **Created**: 2021-10-17
- **Last Updated**: 2022-07-05

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README


# 集合类型与参数类型举例

``` csharp

/// <summary>
/// 参数类，设置为可空类型，不给值就不参与组装linq
/// </summary>
public class BoxQuery
{
    [WhereLarger("Width")]
    public float? MinWidth { get; set; }

    [WhereSmallerEqual("Width")]
    public float? MaxWidth { get; set; }

    [WhereSmallerEqual("Weight")]
    public float? MaxWeight { get; set; }
}
```

``` csharp
/// <summary>
/// Box (实体类)
/// </summary>
public class Box
{
    public int Id { get; set; }
    public float Width { get; set; }
    public float Height { get; set; }
    public float Weight { get; set; }
    public string Description { get; set; }
    public string Remark { get; set; }
}
```

# 使用示范

为`IEnumerable`数据集提供拓展 `GetList<TParam>(TParam input)` 

``` csharp
// var result = boxes.Where(t => t.Width<=60 && t.Weight<=400) 
List<Box> result = boxes.GetList(new BoxQuery
{
    MaxWidth = 60,
    MaxWeight = 400
});
```

为实现了`IQueryable`的仓储等提供拓展`BuildLambda<TParam>(TParam input)`

``` csharp
// 之前
public Task<List<Box>> GetListByParamsAsync(BoxQuery input){
    var query = _repository
        .Where(input.f1 is not null, t=>t.F1==input. f1)
        .Where(input.f2 is not null, t=>t.F1==input. f2)
        .Where(input.f3 is not null, t=>t.F1>input. f3)
        .Where(input.f4 is not null, t=>t.F1<input. f4)
        .Where(!string.IsNullOrWhiteSpace(input.f5), t=>t.F1.Contains(input. f5))
        .Where(input.f6 is not null, t=>t.F1==input. f6)
        .Where(input.f7 is not null, t=>t.F1==input. f7)
        .Where(input.f8 is not null, t=>t.F1==input. f8)
        .Where(input.f9 is not null, t=>t.F1==input. f9)
        .Where(input.f10 is not null, t=>t.F1==input.f10)
        .Where(input.f11 is not null, t=>t.F1==input.f11);
    return await AsyncExecuter.ToListAsync(query);
}

// 之后
public Task<List<Box>> GetListByParamsAsync(BoxQuery input){
// 是否可空由表达式目录树代码判断，使用无需写判断代码。
    var query = _repository.BuildLambda(input);
    return await AsyncExecuter.ToListAsync(query);
}

```

# 支持

- [x]  `WhereEqualAttribute`    `t=> t.Id == input.Id`
- [x] `WhereLikeAttribute`  `t=>t.Name.Contains(input.Id)`
- [x] `WhereLargerAttribute` `t=>t.Age > input.Age`
- [x] `WhereLargerEqualAttribute` `t=>t.Age >= input.Age`
- [x] `WhereSmallerAttribute` `t=>t.Age < input.Age`
- [x] `WhereSmallerEqualAttribute` `t=>t.Age <= input.Age`
- [ ] `WhereInAttribute` `t=>input.Ids.Contains(t.Id)`  `TODO`
- [ ] `WhereBetweenAttribute` 先使用 larger 和 smaller 两个特性共同实现，暂时不增加