/// <summary>
/// between条件转换
/// </summary>
/// <param name="parameter"></param>
/// <param name="conditions"></param>
/// <returns></returns>
private Expression ParaseBetween(ParameterExpression parameter, UosoConditions conditions)
{
ParameterExpression p = parameter;
Expression key = Expression.Property(p, conditions.Key);
var valueArr = conditions.Value.Split(',');
if (valueArr.Length != 2)
{
throw new NotImplementedException("ParaseBetween参数错误");
}
try
{
int.Parse(valueArr[0]);
int.Parse(valueArr[1]);
}
catch
{
throw new NotImplementedException("ParaseBetween参数只能为数字");
}
Expression expression = Expression.Constant(true, typeof(bool));
//开始位置
Expression startvalue = Expression.Constant(int.Parse(valueArr[0]));
Expression start = Expression.GreaterThanOrEqual(key, Expression.Convert(startvalue, key.Type));
Expression endvalue = Expression.Constant(int.Parse(valueArr[1]));
Expression end = Expression.GreaterThanOrEqual(key, Expression.Convert(endvalue, key.Type));
return(Expression.AndAlso(start, end));
}
/// <summary>
/// in条件转换
/// </summary>
/// <param name="parameter"></param>
/// <param name="conditions"></param>
/// <returns></returns>
private Expression ParaseIn(ParameterExpression parameter, UosoConditions conditions)
{
ParameterExpression p = parameter;
Expression key = Expression.Property(p, conditions.Key);
var valueArr = conditions.Value.Split(',');
Expression expression = Expression.Constant(true, typeof(bool));
foreach (var itemVal in valueArr)
{
Expression value = Expression.Constant(itemVal);
Expression right = Expression.Equal(key, Expression.Convert(value, key.Type));
expression = Expression.Or(expression, right);
}
return(expression);
}
private Expression ParseCondition(UosoConditions condition)
{
ParameterExpression p = parameter;
Expression key = Expression.Property(p, condition.Key);
Expression value = Expression.Constant(condition.Value);
switch (condition.Operator)
{
case UosoOperatorEnum.Contains:
return(Expression.Call(key, typeof(string).GetMethod("Contains", new Type[] { typeof(string) }), value)); // 错误细节：https://www.cnblogs.com/goldenbiu/articles/10755120.html
case UosoOperatorEnum.Equal:
return(Expression.Equal(key, Expression.Convert(value, key.Type)));
case UosoOperatorEnum.Greater:
return(Expression.GreaterThan(key, Expression.Convert(value, key.Type)));
case UosoOperatorEnum.GreaterEqual:
return(Expression.GreaterThanOrEqual(key, Expression.Convert(value, key.Type)));
case UosoOperatorEnum.Less:
return(Expression.LessThan(key, Expression.Convert(value, key.Type)));
case UosoOperatorEnum.LessEqual:
return(Expression.LessThanOrEqual(key, Expression.Convert(value, key.Type)));
case UosoOperatorEnum.NotEqual:
return(Expression.NotEqual(key, Expression.Convert(value, key.Type)));
case UosoOperatorEnum.In:
return(ParaseIn(p, condition));
case UosoOperatorEnum.Between:
return(ParaseBetween(p, condition));
default:
throw new NotImplementedException("不支持此操作");
}
}