Question

您好我正在尝试重新命名名为ZverejnenyUcetType的数组类型，但问题是该数组可能包含两种类型：StandartniUcetType和NestandardniUcetType。

所以问题是当我尝试像这样返回数组时：

  string[] dic_vstup = new string[] { (line) };
            RozhraniWSDL.InformaceOPlatciType[] dic_vystup;
            RozhraniWSDL.rozhraniCRPDPH srv = new RozhraniWSDL.rozhraniCRPDPH();
            StatusType status = srv.getStatusNespolehlivyPlatce(dic_vstup, out dic_vystup);
            string abc = status.bezVypisuUctu.ToString();   // If it is already a string, then ToString not needed


            for (int i = 0; i < dic_vystup.Length; i++)
            {
                RozhraniWSDL.InformaceOPlatciType info = dic_vystup[i];


for (int x = 0; x <= 3; x++)
{   
    file2.WriteLine((((RozhraniWSDL.StandardniUcetType)(info.zverejneneUcty[x].Item)).cislo) + "-"

        + (((RozhraniWSDL.StandardniUcetType)(info.zverejneneUcty[x].Item)).cislo) + "/" 

        + (((RozhraniWSDL.StandardniUcetType)(info.zverejneneUcty[x].Item)).kodBanky));     
}}

我遇到以下异常：无法将RozhraniWSDL.NestandardniUcetType类型的对象转换为RozhraniWSDL.StandardniUcetType类型。

NestandardniUcetType只包含一个项目 - cislo

StandartníUcetType有3个项目 - predcislo，cislo，kod banky

这是阵列的图像：

enter image description here

我认为解决方案可能是确定哪个结果属于StandartniUcetType类型，哪个是NestandardniUcetType。

我想问一下这是否可行？

我发现这种解决方案更常见。

感谢您的时间。

Answer 1

如果数组有两种不同的类型，您可以添加if语句，如下所示：

if (info.zverejneneUcty[x].Item is RozhraniWSDL.StandardniUcetType) {
    ...
} else {
    ...
}

稍微好一点的方法是使用as运算符进行投射，如下所示：

RozhraniWSDL.StandardniUcetType std = info.zverejneneUcty[x].Item as RozhraniWSDL.StandardniUcetType;
if (std != null) {
    ...
}
RozhraniWSDL.NestandardniUcetType nstd = info.zverejneneUcty[x].Item as RozhraniWSDL.NestandardniUcetType;
if (nstd != null) {
    ...
}

最后，一个非常好的方法是为这两种类型编写两个单独的方法，并使用dynamic来执行调度。为此，请定义两个函数，如下所示：

static void WriteToFile(RozhraniWSDL.StandardniUcetType std, StreamWriter file) {
    ...
}
static void WriteToFile(RozhraniWSDL.NestandardniUcetType nstd, StreamWriter file) {
    ...
}

现在按如下方式更改循环：

for (int x = 0; x <= 3; x++) {
    dynamic item = info.zverejneneUcty[x].Item;
    WriteToFile(item, file2); // <<== Magic
}

Answer 2

在数组上使用OfType扩展方法将过滤所需的类型

foreach (var item in info.zverejneneUcty.OfType<RozhraniWSDL.StandardniUcetType>())
{
  file2.WriteLine(item.predcislo + "-" + item.cislo + "-" + item.kodBanky);
}

Answer 3

我会通过抽象类重新设计类型并删除问题，如下所示：

// I'm making up the inner types, adapt this to your code
public abstract class UcetType
{
    public virtual object predcislo { get; set; }
    public virtual object cislo { get; set; }
    public virtual object kodBanky { get; set; }

    public virtual void WriteToFile(StreamWriter file) 
    { 
        // build the string and write it to the file
        // considering all properties
        // this acts as "default" for this type and all derived ones
    }
}

public class StandardniUcetType : UcetType
{
    // This will use the abstract as-is
    // with all 3 properties and the "default" WriteToFile() method
}

public class NestandardniUcetType : UcetType
{
    /// <summary>
    /// Attempting to use this will throw an exception
    /// </summary>
    public override object predcislo
    {
        get { throw new NotSupportedException(); }
        set { throw new NotSupportedException(); }
    }
    /// <summary>
    /// Attempting to use this will throw an exception
    /// </summary>
    public override object kodBanky
    {
        get { throw new NotSupportedException(); }
        set { throw new NotSupportedException(); }
    }

    // change the way WriteToFile behaves
    public override void WriteToFile(StreamWriter file)
    {
        // build the string and write it to the file
        // only considering 'cislo' property
    }
}

// Usage example, based on question
for (int i = 0; i < dic_vystup.Length; i++)
{
    RozhraniWSDL.InformaceOPlatciType info = dic_vystup[i];   

    // I assume "3" is the expected length of the array ? Change the for like this:
    for (int x = 0; x <= info.zverejneneUcty.Length; x++)
    {   
        //Delegate to the WriteToFile() method the task to build and write the line!
        info.zverejneneUcty[x].Item.WriteToFile(file2);
    }
}

我认为dynamic方法没有任何好处。这在将来更易读和易于扩展（需要新类型？只需在新类中派生UcetType并重写）。

从包含两种类型结果的数组返回结果

3 个答案: