C# 我可以用 lambda 缩短 if/else 语句吗？
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Can I shorten an if/else statement with lambda?
提问by vwdewaal
I have the following statement as part of building a datarow for a datatable and I was wondering if I could shorten it using a lambda statement or anything more elegant.
我有以下语句作为为数据表构建数据行的一部分，我想知道是否可以使用 lambda 语句或更优雅的语句来缩短它。
if (outval(line.accrued_interest.ToString()) == true)
{
temprow["AccruedInterest"] = line.accrued_interest;
}
else
{
temprow["AccruedInterest"] = DBNull.Value;
}
The statement is checked by:
该语句由以下人员检查：
public static bool outval(string value)
{
decimal outvalue;
bool suc = decimal.TryParse(value, out outvalue);
if (suc)
{
return true;
}
else
{
return false;
}
}
采纳答案by Sriram Sakthivel
public static bool outval(string value)
{
decimal outvalue;
return decimal.TryParse(value, out outvalue);
}
temprow["AccruedInterest"] = outval(line.accrued_interest.ToString()) ? (object)line.accrued_interest : (object)DBNull.Value;
Edit:casting to objectis important since ?:ternary operator needs to return results both true case and false case has to be implicitly converted to other. I don't know what is type of accrued_interestI assume it will be a doubleor decimalsince there is no implicit conversion between decimaland DBNull. In order to make it work you've to cast to objecttype.
Is that clear?
编辑：转换为object很重要，因为?:三元运算符需要返回结果，true case 和 false case 必须隐式转换为 other。我不知道什么是类型，accrued_interest我认为它将是 adouble或者decimal因为decimal和之间没有隐式转换DBNull。为了使其工作，您必须强制转换为object类型。明白了吗？
回答by Ehsan
You don't need to call a separate method. No need of method or any other things
您不需要调用单独的方法。不需要方法或任何其他东西
decimal result;
if(decimal.TryParse(line.accrued_interest.ToString(),out result))
temprow["AccruedInterest"] = line.accrued_interest
else
temprow["AccruedInterest"] = DBNull.Value;
回答by Zac
You want the ? Operator, you don't need a lambda expression.
你想要吗？运算符，您不需要 lambda 表达式。
http://msdn.microsoft.com/en-us/library/ty67wk28.aspx
http://msdn.microsoft.com/en-us/library/ty67wk28.aspx
int input = Convert.ToInt32(Console.ReadLine());
string classify;
// if-else construction.
if (input < 0)
classify = "negative";
else
classify = "positive";
// ?: conditional operator.
classify = (input < 0) ? "negative" : "positive";
回答by Blank
Also,
还，
public static bool outval(string value)
{
decimal outvalue;
bool suc = decimal.TryParse(value, out outvalue);
if (suc)
{
return true;
}
else
{
return false;
}
}
To..
到..
public static bool outval(string value)
{
decimal outvalue;
return decimal.TryParse(value, out outvalue);
}
