/// <summary>
/// 从mapping 中寻找指定的属性名 如果找不到 返回属性名
/// </summary>
/// <param name="sqlFieldMapping"></param>
/// <param name="propName"></param>
/// <returns></returns>
internal static string SearchPropertyMappingField(SqlFieldMapping sqlFieldMapping, string propName)
{
if (null == sqlFieldMapping)
{
return(propName);
}
var field = sqlFieldMapping.Filelds.FirstOrDefault(x => x.PropertyName == propName);
if (null == field)
{
return(propName);
}
return(field.FieldColumnName);
}
/// <summary>
/// 解析Lambda 到Where条件表达式
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="func"></param>
/// <param name="sqlFieldMapping"></param>
/// <param name="wrapperChar">字段的包裹符号</param>
/// <returns></returns>
internal static string ConvertLambdaToCondition <T>(Expression <Func <T, bool> > func, SqlFieldMapping sqlFieldMapping, string wrapperChar = "") where T : BaseEntity
{
var whereStr = string.Empty;
if (func.Body is BinaryExpression)
{
BinaryExpression be = ((BinaryExpression)func.Body);
Expression originalLeft = be.Left;
Expression originalRight = be.Right;
Expression afterProcessLeft = ProcessNoneValueBoolenExpression <T>(originalLeft);
Expression afterProcessRight = ProcessNoneValueBoolenExpression <T>(originalRight);
whereStr = BinarExpressionProvider(afterProcessLeft, afterProcessRight, be.NodeType, sqlFieldMapping, wrapperChar);
//whereStr = BinarExpressionProvider(be.Left, be.Right, be.NodeType);
}
if (func.Body is MethodCallExpression)
{
MethodCallExpression mce = ((MethodCallExpression)func.Body);
string methodCondition = ExpressionRouter(mce, sqlFieldMapping);
if (!string.IsNullOrEmpty(methodCondition))
{
if (whereStr != string.Empty)
{
whereStr += " and ";
whereStr += methodCondition;
}
else
{
whereStr = methodCondition;
}
}
}
return(whereStr);
}
static string ExpressionRouter(Expression exp, SqlFieldMapping sqlFieldMapping, string wrapperChar = "")
{
string sb = string.Empty;
if (exp is BinaryExpression)
{
BinaryExpression be = ((BinaryExpression)exp);
return(BinarExpressionProvider(be.Left, be.Right, be.NodeType, sqlFieldMapping, wrapperChar));
}
else if (exp is MemberExpression)
{
if (!exp.ToString().StartsWith("value("))
{
MemberExpression me = ((MemberExpression)exp);
string filedName = SearchPropertyMappingField(sqlFieldMapping, me.Member.Name);
return(string.Concat(wrapperChar, filedName, wrapperChar));
}
else
{
ConstantExpression conExpression = null;
TryEvaluatePath(exp, out conExpression);
var result = conExpression.Value;
if (result == null)
{
return("null");
}
if (result is ValueType && !(result is Guid) && !(result is DateTime)) //guid 虽然是值类型的 --长整型，datetime 是struct 也是继承值类型 但是在SQL操作的时候 是按照字符串处理的
{
if (result is Enum)
{
return(((int)result).ToString()); //枚举类型的 要转换为具体的int 值
}
return(result.ToString());
}
else if (result is string || result is DateTime || result is char || result is Guid)
{
if (result is DateTime)
{
//将时间进行统一 yyyy-MM-dd HH:mm:ss
return(string.Format("'{0}'", ((DateTime)result).ToOfenTimeString()));
}
return(string.Format("'{0}'", result.ToString()));
}
}
}
else if (exp is NewArrayExpression)
{
NewArrayExpression ae = ((NewArrayExpression)exp);
StringBuilder tmpstr = new StringBuilder();
foreach (Expression ex in ae.Expressions)
{
tmpstr.Append(ExpressionRouter(ex, null));
tmpstr.Append(",");
}
return(tmpstr.ToString(0, tmpstr.Length - 1));
}
else if (exp is MethodCallExpression)
{
MethodCallExpression mce = (MethodCallExpression)exp;
if (mce.Method.Name == "Like")
{
return(string.Format("({2}{0}{2} like {1})", ExpressionRouter(mce.Arguments[0], sqlFieldMapping), ExpressionRouter(mce.Arguments[1], null), wrapperChar));
}
else if (mce.Method.Name == "Contains")
{
return(string.Format("({2}{0}{2} like {1})", ExpressionRouter(mce.Object, sqlFieldMapping), ExpressionRouter(mce.Arguments[0], null), wrapperChar));
}
else if (mce.Method.Name == "NotLike")
{
return(string.Format("({2}{0}{2} Not like {1})", ExpressionRouter(mce.Arguments[0], sqlFieldMapping), ExpressionRouter(mce.Arguments[1], null), wrapperChar));
}
else if (mce.Method.Name == "In")
{
return(string.Format("{{2}{0}{2} In ({1})", ExpressionRouter(mce.Arguments[0], sqlFieldMapping), ExpressionRouter(mce.Arguments[1], null), wrapperChar));
}
else if (mce.Method.Name == "NotIn")
{
return(string.Format("{2}{0}{2} Not In ({1})", ExpressionRouter(mce.Arguments[0], sqlFieldMapping), ExpressionRouter(mce.Arguments[1], null), wrapperChar));
}
else if (mce.Method.Name == "LenFuncInSql")
{
return(string.Format("len({1}{0}{1})", ExpressionRouter(mce.Arguments[0], sqlFieldMapping), wrapperChar));
}
else
{
//实例方法或者静态方法的调用解析
if (null != mce.Object)
{
//如果不是自定义的内置sql函数方法 活着扩展， 那么只取属性;例如 x.Id.ToString() .那么仅仅返回id属性即可
var mceValue = ExpressionRouter(mce.Object, sqlFieldMapping);
if (null != mceValue)
{
return(mceValue); //string.Format("{1}{0}{1}", mceValue, wrapperChar);
}
else
{
//解析不是基础类型 时候 尝试执行表达式
object result = Expression.Lambda(mce).Compile().DynamicInvoke();
ConstantExpression consExpress = Expression.Constant(result);
return(ExpressionRouter(consExpress, sqlFieldMapping));
}
}
else
{
//如果是System 处理函数 调用 那么执行函数调用的结果
object result = Expression.Lambda(mce).Compile().DynamicInvoke();
ConstantExpression consExpress = Expression.Constant(result);
return(ExpressionRouter(consExpress, sqlFieldMapping));
}
}
}
else if (exp is ConstantExpression)
{
ConstantExpression ce = ((ConstantExpression)exp);
if (ce.Value == null)
{
return("null");
}
else if (ce.Value is ValueType)
{
if (ce.Value is Guid || ce.Value is DateTime) //处理guid值
{
return(string.Format("'{0}'", ce.Value.ToString()));
}
return(ce.Value.ToString());//处理bool值 ce.Value is bool
}
else if (ce.Value is string || ce.Value is DateTime || ce.Value is char)
{
return(string.Format("'{0}'", ce.Value.ToString()));
}
}
else if (exp is UnaryExpression)
{
UnaryExpression ue = ((UnaryExpression)exp);
return(ExpressionRouter(ue.Operand, sqlFieldMapping));
}
return(null);
}
static string BinarExpressionProvider(Expression left, Expression right, ExpressionType type, SqlFieldMapping sqlFieldMapping, string wrapperChar = "")
{
string sb = "(";
//先处理左边
sb += ExpressionRouter(left, sqlFieldMapping, wrapperChar);//左边的字段 传递包裹符号
sb += ExpressionTypeCast(type);
//再处理右边
string tmpStr = ExpressionRouter(right, sqlFieldMapping, wrapperChar);//左边的字段 传递包裹符号
if (tmpStr == "null")
{
if (sb.EndsWith(" ="))
{
sb = sb.Substring(0, sb.Length - 2) + " is null";
}
else if (sb.EndsWith("<>"))
{
sb = sb.Substring(0, sb.Length - 2) + " is not null";
}
}
else
{
sb += tmpStr;
}
return(sb += ")");
}
