无法将 System.Type 隐式转换为对象

Question

我正在尝试创建在 .NET C# 中加载表单设置的通用方法，其中每个设置都将包含它自己的 try catch 块（以便在单个设置无效时继续其他设置）。但是我无法弄清楚如何解决将应用程序设置分配给对象的问题。编译器不允许我隐式转换对象的类型。

private void LoadFormSettings(object o)
{
  try
  {
    //Load settings when application is started
    Type t = o.GetType();

    // Operator '<' cannot be applied to operands of type 'method group' and 'System.Type'
    o = getAppSetting<o.GetType()>("Setting");
    // Cannot implicitly convert type 't' to 'object'
    o = getAppSetting<t>("Setting");
    // The type arguments for method... cannot be inferred from the usage. Try specifying the type arguments explicitly
    o = getAppSetting("Setting");
  }
  catch (Exception ee)
  {
  }
}

private T getAppSetting<T>(string key)
{
  string value = config.AppSettings.Settings[key].Value;
  if (typeof(T) == typeof(Point))
  {
    string[] values = value.Split(',');
    return (T) Convert.ChangeType(value, typeof(T));
  }
}

Answer 1

Type 是类型，t 是实例。泛型需要类型而不是实例。只能写F<Type>()，不能写F<t>()。在你的情况下，最好写

Type t = o.GetType();
o = getAppSetting("Setting", t);

object getAppSetting(string key, Type t)
{
  string value = config.AppSettings.Settings[key].Value;
  if (t == typeof(Point))
  {
    string[] values = value.Split(',');
    return Convert.ChangeType(value, t);
  }
}

Answer 2

您可以使用：

    public T GetAppSetting<T>(string value) where T : struct
    {
        string value = config.AppSettings.Settings[key].Value;
        return (T)Convert.ChangeType(value, default(T).GetType());
    }

var myBoolean = GetAppSetting<bool>("setting");

无法将 System.Type 隐式转换为对象

cannot implicitly convert System.Type to object

c#

casting

object

system.type