DynamicExpressionParser 实现 WhereDynamicFilter 自定义 System.Linq.Dynamic.Core

[2881099]

先了解 WhereDynamicFilter

ISelect.WhereDynamicFilter 方法实现动态过滤条件（与前端交互），支持的操作符：

• Contains/StartsWith/EndsWith/NotContains/NotStartsWith/NotEndsWith：包含/不包含，like '%xx%'，或者 like 'xx%'，或者 like '%xx'
• Equal/NotEqual：等于/不等于
• GreaterThan/GreaterThanOrEqual：大于/大于等于
• LessThan/LessThanOrEqual：小于/小于等于
• Range：范围查询
• DateRange：日期范围，有特殊处理 value[1] + 1
• Any/NotAny：是否符合 value 中任何一项（直白的说是 SQL IN）
• Custom：自定义解析 (后面有 DEMO)

DynamicFilterInfo dyfilter = JsonConvert.DeserializeObject<DynamicFilterInfo>(@"
{
  ""Logic"": ""And"",
  ""Filters"":
  [
    { ""Field"": ""id"", ""Operator"": ""Equals"", ""Value"": 1 },
    {
      ""Logic"": ""Or"",
      ""Filters"":
      [
        { ""Field"": ""id"", ""Operator"": ""Equals"", ""Value"": 2 },
        { ""Field"": ""id"", ""Operator"": ""Equals"", ""Value"": 3 }
      ]
    }
  ]
}");
fsql.Select<Topic>().WhereDynamicFilter(dyfilter).ToList();
//WHERE id = 1 AND (id = 2 OR id = 3)

动态排序：ISelect.OrderByPropertyName("Parent.Code")
动态返回：ISelect.ToDataTableByPropertyName(new string[] { "Parent.Code", "Id" })

实现 DynamicFilterCustom

输入参数为 JSON，{{ DynamicFilterCustomImpl.CustomLinq }} 是一个固定的值，请往后面看 c# 代码

{
  Logic: 'And',
  Filters:
  [
    { Field: 'id', Operator: 'Equals', Value: 1 },
    {
      Logic: 'Or',
      Filters:
      [
        { Field: 'id', Operator: 'Equals', Value: 2 },
        {
            Field: '{{ DynamicFilterCustomImpl.CustomLinq }}', 
            Operator: 'Custom', 
            Value: 'Title.StartsWith(\'new topic 1\')'
        }
      ]
    }
  ]
}

DynamicFilterInfo dyfilter = JsonConvert.DeserializeObject<DynamicFilterInfo>(json);
fsql.Select<Topic>().WhereDynamicFilter(dyfilter).ToList();
// WHERE id = 1 AND (id = 2 OR title like 'new topic 1%')

nuget 安装 System.Linq.Dynamic.Core

//自定义代码
public class DynamicFilterCustomImpl
{
    //JSON Field 对应这个值
    public static string CustomLinq = $"{nameof(DynamicFilterCustomImpl.DynamicLinq)} {typeof(DynamicFilterCustomImpl).FullName},{typeof(DynamicFilterCustomImpl).Assembly.FullName}";

    [DynamicFilterCustom]
    public static LambdaExpression DynamicLinq(object sender, string value)
    {
        if (string.IsNullOrWhiteSpace(value)) value = "1==2";
        ParameterExpression t = Expression.Parameter(sender.GetType().GetGenericArguments()[0], "t");
        var exp = DynamicExpressionParser.ParseLambda(new ParameterExpression[] { t }, typeof(bool), value);
        return exp;
    }
}

[2881099]

搬运工 from #1113