public override object Execute(Expression expression)
{
String url = GetQueryText(expression);
IEnumerable <Post> results = PostHelper.PerformWebQuery(url);
return(results);
}
public override String GetQueryText(Expression expression)
{
SearchCriteria criteria;
// 翻译查询条件
criteria = new PostExpressionVisitor().ProcessExpression(expression);
// 生成URL
String url = PostHelper.BuildUrl(criteria);
return(url);
}