将Type强制转换为类

本文关键字：转换 Type | 更新日期: 2023-09-27 18:09:03

如果我有一个这样定义的类:

public class className
{
    public object this[string propertyName]
    {
        get { return this.GetType().GetProperty(propertyName).GetValue(this, null); }
        set { this.GetType().GetProperty(propertyName).SetValue(this, value, null); }
    }
    public string Foo{ get; set; }
    public string Bar { get; set; }

我当然可以这样设置和获取这些值:

className d = new className();
d["Foo"]="abcd" // set
string s = (string)f["Bar"];

(感谢Eduardo Cuomo的回答)

但是我真正想做的是:

Type target = Type.GetType(DocumentType);
// loop through list of key-value pairs and populate the data class defined in target object Type
foreach (Dictionary<string, string> PQList in LPQReq)
{
foreach (KeyValuePair<string, string> kvp in PQList)
{
    // populate the member in the data class with the value from the MQ String
    target[kvp.Key] = kvp.Value;                                                
    }

但是这不会编译成Cannot apply indexing with [] to an expression of type 'System.Type'

我该怎么做呢?

我当然可以使用dynamic，但也许有一种方法将我的类型转换为我的目标类?

将Type强制转换为类

你可以用反射来做。假设所有可能的DocumentType都有一个无参数构造函数，您可以这样做:

// Get the type (this comes from your example)
Type target = Type.GetType(DocumentType);
// Create an instance (that's the important part that was missing)
object instance = Activator.CreateInstance(target);
foreach (Dictionary<string, string> PQList in LPQReq) {
    foreach (KeyValuePair<string, string> kvp in PQList) {
        // This code again comes from your example,
        // except propertyName is kvp.Key and value is kvp.Value
        target.GetProperty(kvp.Key).SetValue(instance, kvp.Value, null);
    }
}

为了访问索引器，您需要实例化该类型，并且需要将其强制转换为具有索引器的对象。

你可以定义一个接口:

public interface IIndexable_String
{
    object this[string index]
    {
        get;
        set;
    }
}

应用到你的类中:

public class someclass : IIndexable_String

然后实例化实例并访问索引器

Type target = Type.GetType(DocumentType);
// Instantiate
IIndexable_String instance = (IIndexable_String)Activator.CreateInstance(target);
foreach (Dictionary<string, string> PQList in LPQReq)
{
    foreach (KeyValuePair<string, string> kvp in PQList)
    {
        // populate the member in the data class with the value from the MQ String
        instance[kvp.Key] = kvp.Value;                                                
    }

当然，如果您像@dasblinkenlight那样做，您甚至不需要类中神奇的getter和setter，也不需要接口。

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