C#长切换语句
本文关键字:语句 | 更新日期: 2023-09-27 18:00:30
我看过StackOverflow上关于c++长切换语句的文章,但c#在这方面有所不同。
具体来说,我想在c#代码中替换一个非常长的switch语句,其中每个case语句都做相同的事情,只是字段名称发生了变化。
代码如下:
case Fields.TRANSMITTERCONTACTPHONEEXT:
{
int lengthNeeded = 0;
int currentLength = TransmitterContactTelephoneExtension.Length;
int lengthRequired = TransmitterContactTelephoneExtensionLength;
if (currentLength < lengthRequired)
{
lengthNeeded = lengthRequired - currentLength;
for (int i = 0; i < lengthNeeded; i++)
{
TransmitterContactTelephoneExtension += " ";
}
}
} break;
case Fields.TRANSMITTERFEIN:
{
int lengthNeeded = 0;
int currentLength = TransmitterFEIN.Length;
int lengthRequired = TransmitterFEINLength;
if (currentLength < lengthRequired)
{
lengthNeeded = lengthRequired - currentLength;
for (int i = 0; i < lengthNeeded; i++)
{
TransmitterFEIN += " ";
}
}
} break;
我只想把它归结为一个函数,它可以在不必使用switch语句的情况下计算出我指的是哪个字段。有没有一种方法可以传入包含字段名称的变量?
将所有可变值放入数组并对其进行索引。确保enum int值与目标数组中的数据相同。
var current = (int) Fields.TRANSMITTERCONTACTPHONEEXT;
int lengthNeeded = 0;
int currentLength = LengthData[ current ] ;
int lengthRequired = RequiredData[current ];
if (currentLength < lengthRequired)
{
lengthNeeded = lengthRequired - currentLength;
for (int i = 0; i < lengthNeeded; i++)
{
Extensions[ current ] = Extensions[ current ] + " ";
}
}
这篇文章着眼于交换机中操作的模式,并没有解决单个操作的任何局部缺陷。请查看每个单独的操作,并在需要的地方进行改进,以获得最佳的操作效率。
这看起来就像一个字符串填充函数的代码重复了多次。你可以有
case Fields.TRANSMITTERCONTACTPHONEEXT:
TransmitterContactTelephoneExtension = TransmitterContactTelephoneExtension.PadRight(TransmitterContactTelephoneExtensionLength, ' ');
break;
...
每当你发现自己一遍又一遍地重复代码时,你可能会把它分解成一个单独的函数(如果还不存在的话),然后用正确的参数调用它
这也让我怀疑你是否需要switchcase语句,而不仅仅是一系列pad语句。但这在您的代码中(在范围内)会更进一步。你的帖子没有给我们足够的信息去那里
最后,在某种程度上适用于你的问题,我的经验法则(最初不是我的,但我忘了我从哪里得到的)是,如果一个方法超过了一页(故意模糊的术语),那么我需要将其分解为其他单独的方法。这使我能够在不滚动的情况下查看方法并理解它。它还迫使我把一个较长的过程分成较小的逻辑步骤。
您真的应该把它分解成一个方法。这样就不会一遍又一遍地重复代码。这是低效的,并且在更新时可能导致潜在的错误。
此外,您应该在字符串上使用PadRight()方法,而不是循环。
我会这样做:
case Fields.TRANSMITTERCONTACTPHONEEXT:
TransmitterContactTelephoneExtension = PadString(TransmitterContactTelephoneExtensionLength, TransmitterContactTelephoneExtension);
break;
case Fields.TRANSMITTERFEIN:
TransmitterFEIN = PadString(TransmitterFEINLength, TransmitterFEIN);
break;
private string PadString(int requiredLen, string value)
{
if (value == null) return String.Empty.PadRight(requiredLen, ' '); //Create an empty string when the value is null
return value.PadRight(requiredLen, ' ');
}
提前声明变量,并仅对不同的赋值使用switch
:
int currentLength;
int lengthRequired;
switch (whatever) {
case Fields.TRANSMITTERCONTACTPHONEEXT:
currentLength = TransmitterContactTelephoneExtension.Length;
lengthRequired = TransmitterContactTelephoneExtensionLength;
break;
case Fields.TRANSMITTERFEIN:
currentLength = TransmitterFEIN.Length;
lengthRequired = TransmitterFEINLength;
break;
default:
throw new Exception(); // Without this, the compiler will complain about uninitialized variables
}
int lengthNeeded = 0;
if (currentLength < lengthRequired)
{
lengthNeeded = lengthRequired - currentLength;
for (int i = 0; i < lengthNeeded; i++)
{
TransmitterFEIN += " ";
}
}
switch (whatever) {
case Fields.TRANSMITTERCONTACTPHONEEXT:
TransmitterContactTelephoneExtension += " ";
break;
case Fields.TRANSMITTERFEIN:
TransmitterFEIN += " ";
break;
}
编辑:如果您可以选择用数组替换变量,OmegaMan的解决方案会更好。
对我来说,我们看不到的代码似乎需要一些重构,但根据我们所看到的,我建议执行以下操作:
// 1. Have a class to hold your data
class FieldData
{
public string Value { get; set; }
public int LengthRequired { get; set; }
public string RightPaddedValue
{
get { return Value.PadRight(LengthRequired, ' '); }
}
}
// 2. Fill your data into a dictionary somehow... for example:
Dictionary<Fields, FieldData> fields = new Dictionary<Fields, FieldData>
{
{
Fields.TRANSMITTERCONTACTPHONEEXT,
new FieldData {
Value = TransmitterContactTelephoneExtension,
LengthRequired = TransmitterContactTelephoneExtensionLength
}
},
{
Fields.TRANSMITTERFEIN,
new FieldData {
Value = TransmitterFEIN,
LengthRequired = TransmitterFEINLength
}
}
};
// 3. Then use the data from that dictionary in your code:
FieldData data = fields[selectedField];
data.RightPaddedValue; // use RightPaddedValue