Question

public class Constants
{
    public const string test1 = "This is testvalue1;"
    public const string test2 = "This is testvalue1;"
    public const string test3 = "This is testvalue1;"
    public const string test4 = "This is testvalue1;"
    public const string test5 = "This is testvalue1;"
}

是否可以通过使用var propertyString = Constants.Where(<Propertyname> == test1).ToString()来获取常量字符串？

Answer 1

你必须通过反思来做到这一点。

string fieldName = "test1";
object fieldValue = typeof(Constants).GetField(fieldName, BindingFlags.Static).GetValue(null);

Answer 2

除了其他面向反射的答案，您可以使用字典：

public string GetConstantValue(string key)
{
  return _constants[key];
}

private Dictionary<string, string> Constants = new Dictionary<string, string>()
{
  { "test1", "This is testvalue1;" },
  { "test2", "This is testvalue2;" },
  { "test3", "This is testvalue3;" },
  { "test4", "This is testvalue4;" },
  { "test5", "This is testvalue5;" },
};

然后使用MyClass.GetConstantValue("test1")获取常量值。

Answer 3

这也可行：

    foreach (var prop in typeof(Constants).GetFields())
    {
        string test = prop.GetRawConstantValue().ToString();

        if (test == "test1")
            MessageBox.Show("You got me!");
    }

Answer 4

您可以使用Reflection。

List<string> messages = new List<string>();
foreach (FieldInfo field in typeof(Constants).GetFields().Where(f =>         f.Name.StartsWith("test")))
{
   messages.Add(field.GetRawConstantValue().ToString());

}

Answer 5

为了得到这个，

var p = Constants.Get("test1");//gives 'This is testvalue1'

你可以这样做 -

public class Constants
{
    public const string test1 = "This is testvalue1";
    public const string test2 = "This is testvalue1";
    public const string test3 = "This is testvalue1";
    public const string test4 = "This is testvalue1";
    public const string test5 = "This is testvalue1";

    public static string Get(string propertyName)
    {
      var value = (string)(typeof(Constants).GetField(propertyName,BindingFlags.Static | BindingFlags.Public).GetValue(null));
      return value;
    }
}

Answer 6

当然有可能。下面的代码使用反射来遍历类的所有常量。

internal class Program
{
    public const string ConstExample = "constant value";

    private static void Main(string[] args)
    {
        FieldInfo[] fieldInfos = typeof(Program).GetFields(BindingFlags.Public | BindingFlags.Static | BindingFlags.FlattenHierarchy);

        var constants = fieldInfos.Where(z => z.IsLiteral && !z.IsInitOnly).ToList();
        foreach (var constant in constants)
        {
            string constantName = constant.Name;
            object constantValue = constant.GetValue(null);
            Console.WriteLine(string.Format("Constante name: {0}, constant value: {1}", constantName, constantValue));
        }

        Console.ReadKey();
    }
}

Answer 7

为了获得良好的性能和可读性，我建议使用数组和枚举。

class App
{
    private enum ConstantsEnum: int
    {
      DefaultName = 0,
      DefaultMode = 1,
      DefaultStatus = 2
    }
    private readonly string[] Constants = new string[]{
        "MyProgram",
        "Test",
        "Enabled" };

    private void DoWork()
    {
        Console.WriteLine(Constants[ConstantsEnum.DefaultName]);
    }
}

请注意，所有变量都必须是string类型。如果您想混合和匹配数据类型，那么您可以使用object[]而不是string[]，但这样会更昂贵而且不是类型安全的。

如果您只是想找到一种方法来对某些属性进行分组，那么这比反射要好得多。

按属性名从列表中选择常量

7 个答案: