/*** Answer with the comments in code ***/
// don't create a class to represent your criteria
// Dictionary is enough for use and supported by Linq
// don't use a lot of `&&` or `if`; one `if` is enough
// all the rules is in deferred execution, only executes when it really needs
// evaluated and the order to put where clauses matters, don't make it changed
// it performs like short-circuit evaluation
/// <summary>
/// declared as partial for easily coexists with original code
/// if not used(e.g already declared) then not paste to file
/// </summary>
partial class AccountDto /* known members */ {
public int Accountid;
public int Userid;
public String Holdername;
public int Balance;
public String Status;
}
/// <summary>
/// declared as partial for easily coexists with original code
/// if getSearchedAccount is declared with another class name
/// then just rename the partial class to that name and remove
/// all `static`(if that class is non-static)
/// the class initializer, then become constructor; remember to
/// match the name of class and constructor
/// </summary>
partial class AccountDto {
/// <summary>
/// declare as static for this demo;
/// not necessarily be static if it's declared in another
/// class where list is declared
/// </summary>
public static List<AccountDto> getSearchedAccount(
int accountid, int userid,
String holdername, String type,
double balance,
String status
) {
var results=new List<AccountDto>();
// make a copy of IgnoreRules and clear; equivalent to
// var matchRules=new Dictionary<String, Func<AccountDto, bool>>();
// IgnoreRules is not changed with these two statement
// just prevent to see too many angle braces
var matchRules=IgnoreRules.ToDictionary(x => x.Key, x => x.Value);
matchRules.Clear();
// the parameters only known in this method thus can only added here
matchRules.Add("accountid", x => accountid==x.Accountid);
matchRules.Add("userid", x => userid==x.Userid);
matchRules.Add("holdername", x => holdername==x.Holdername);
matchRules.Add("balance", x => balance==x.Balance);
matchRules.Add("status", x => status==x.Status);
for(int i=0; i<list.Count; i++) {
var dto=(AccountDto)list[i];
if((from ignoreRule in IgnoreRules
from matchRule in matchRules
where ignoreRule.Key==matchRule.Key
where !ignoreRule.Value(dto)
select matchRule.Value(dto)).All(x => x))
results.Add(dto);
}
return results;
}
/// <summary>
/// criteria for `don't test for matching`
/// </summary>
public static Dictionary<String, Func<AccountDto, bool>> IgnoreRules {
get;
set;
}
/// <summary>
/// use class initializer to add common IgnoreRules
/// </summary>
static AccountDto() {
IgnoreRules=new Dictionary<String, Func<AccountDto, bool>>();
IgnoreRules.Add("accountid", x => 0==x.Accountid);
IgnoreRules.Add("userid", x => 0==x.Userid);
IgnoreRules.Add("holdername", x => String.IsNullOrEmpty(x.Holdername));
IgnoreRules.Add("balance", x => 0==x.Balance);
IgnoreRules.Add("status", x => String.IsNullOrEmpty(x.Status));
}
/// <summary>
/// declare as static for this demo;
/// not necessarily be static if it's declared in another
/// class where getSearchedAccount is declared
/// </summary>
public static List<AccountDto> list=new List<AccountDto>();
}
您是否擁有穩定數量的'Properties'？否則這個解決方案最終會炸燬你的代碼。 – 2013-03-08 15:17:05
yes屬性是穩定的 – 2013-03-08 15:20:15
您可能還想將基本類型參數'accountid'，'userid'和'balance'設置爲[可空屬性]（http://msdn.microsoft.com/en-us/library /b3h38hb0.aspx）（例如'int？'或'double？'），所以你可以傳遞'null'而不是像'0'這樣的模糊值。 – mellamokb 2013-03-08 15:26:56