QueryFilter 类

此类包含谓词过滤器值。

public class QueryFilter
{
    public string PropertyName { get; set; }
    public string Value { get; set; }
    public Operator Operator { get; set; }

    // In the query {a => a.Name.Equals("Pedro")} 
    // Property name to filter - propertyName = "Name"
    // Filter value - value = "Pedro"
    // Operation to perform - operation = enum Operator.Equals
    public QueryFilter(string propertyName, string value, Operator operatorValue)
    {
        PropertyName = propertyName;
        Value = value;
        Operator = operatorValue;
    }       
}

枚举以保存操作值：

 public enum Operator
{
    Contains,
    GreaterThan,
    GreaterThanOrEqual,
    LessThan,
    LessThanOrEqualTo,
    StartsWith,
    EndsWith,
    Equals,
    NotEqual
}