private void Eval(Expression _Expression, ParserArgs _ParserArgs)
{
UnaryExpression cast = Expression.Convert(_Expression, typeof(object));
var obj = Expression.Lambda <Func <object> >(cast).Compile().Invoke();
if (obj == null)
{
_ParserArgs.AddParameter(obj);
}
else
{
var type = obj.GetType();
if (type.Name == "List`1") //list集合
{
var list = obj as IEnumerable;
var index = 0;
foreach (var item in list)
{
_ParserArgs.AddParameter(item.ToStr());
index = _ParserArgs.Builder.Length;
_ParserArgs.Builder.Append(",");
}
_ParserArgs.Builder.Remove(index, 1);
}
else
{
_ParserArgs.AddParameter(obj);
}
}
}
public override void Where(MemberExpression expr, ParserArgs args)
{
if (expr.Expression is ParameterExpression)
{
if (args.TabIsAlias)//在字段上是否加上表的别名
{
Parser.Where(expr.Expression, args);
}
args.Builder.Append(expr.Member.Name);
args.Builder.Append(' ');
}
else
{
object val = Helper.GetValue(expr);
args.Builder.Append(' ');
IEnumerator array = val as IEnumerator;
if (array != null)
{
AppendArray(args, array);
}
else if (val is Array)//else if (val is IEnumerable)
{
AppendArray(args, ((IEnumerable)val).GetEnumerator());
}
else
{
args.AddParameter(val);
}
}
}
public override void Where(UnaryExpression expr, ParserArgs args)
{
//Parser.Where(expr.Operand, args);
var val = Helper.Eval_1(expr.Operand);
args.Builder.Append(' ');
args.AddParameter(val);
}
/// <summary> 追加可遍历对象(数组或集合或简单迭代器)
/// </summary>
private static void AppendArray(ParserArgs args, IEnumerator array)
{
if (array.MoveNext())
{
args.Builder.Append('(');
args.AddParameter(array.Current);
while (array.MoveNext())
{
args.Builder.Append(',');
args.AddParameter(array.Current);
}
args.Builder.Append(')');
}
else
{
args.Builder.Append("NULL");
}
}
private void DealNewArrayExpression(NewArrayExpression _Expression, ParserArgs _ParserArgs)
{
StringBuilder tmpstr = new StringBuilder();
foreach (Expression ex in _Expression.Expressions)
{
tmpstr.Append("'" + this.Eval(ex) + "'");
tmpstr.Append(",");
}
_ParserArgs.AddParameter(tmpstr.ToString(0, tmpstr.Length - 1));
}
public override void Where(ConstantExpression expr, ParserArgs args)
{
args.Builder.Append(' ');
args.AddParameter(expr.Value);
}