public class MyCurrency{  public uint Dollars;  public ushort Cents;  public MyCurrency(uint dollars, ushort cents)  {    this.Dollars = dollars;    this.Cents = cents;  }  public override string ToString()  {    return string.Format(      "${0}.{1}", Dollars, Cents    );  }  //提供MyCurrency到float的隱式轉換  public static implicit operator float(MyCurrency value)  {    return value.Dollars + (value.Cents / 100.0f);  }  //把float轉換為MyCurrency,不能保證轉換肯定成功,因為float可以  //存儲負值,而MyCurrency只能存儲正數  //float存儲的數量級比uint大的多，如果float包含一個比unit大的值，  //將會得到意想不到的結果，所以必須定義為顯式轉換  //float到MyCurrency的顯示轉換  public static explicit operator MyCurrency(float value)  {    //checked必須加在此處，加在調用函數外面是不會報錯的，    //因為溢出的異常是在強制轉換運算符的代碼中發生的    //Convert.ToUInt16是為了防止丟失精度    //該段內容很重要，詳細參考"C#高級編程(中文第七版) 218頁說明"    checked    {      uint dollars = (uint)value;      ushort cents = Convert.ToUInt16((value - dollars) * 100);      return new MyCurrency(dollars, cents);    }  }}

private void btn_測試自定義類型強制轉換_Click(object sender, EventArgs e){  MyCurrency tmp = new MyCurrency(10, 20);  //調用MyCurrency到float的隱式轉換  float fTmp = tmp;  MessageBox.Show(fTmp.ToString());  float fTmp2 = 200.30f;  //調用float到MyCurrency的顯示轉換  MyCurrency tmp2 = (MyCurrency)fTmp2;  MessageBox.Show(tmp2.ToString());}