属性或索引器不能分配给“ - ”它是只读的 [英] Property or indexer cannot be assigned to "--" it is read only

问题描述

我有以下代码

  private   readonly   string  _cstrvalueMember;  //  保留值 
  private   readonly   string  _cstrdisplayMember; 
 
  object  obj; 
 LookupDTO lkpDTOo =（LookupDTO）obj; 
  if （lkpDTOo.strValueMember ==   3）
 {
 lkpDTOo.strDisplayMember =    - ; 
} 

但 lkpDTOo.strDisplayMember = - ; 这里我收到的错误如< pre lang =vb> 错误 50 Property 或 indexer ' XXX.DTO.LookupDTO.strDisplayMember '无法分配 - 它是只读的

即使我删除了readonly并将其公开，但它不是working

解决方案

您还没有在班级中为 strDisplayMember 定义setter。



尝试

  public   string  strDisplayMember 
 {
  get  { return  _cstrdisplayMember; } 
  set  { this  ._ cstrdisplayMember =  value ; } 
 
} 

你和strValueMember有类似的问题。



这是一个刷新的参考< a href =http://www.dotnetperls.com/property>属性 [ ^ ]

您必须了解变量的范围和访问权限！

这里有一个只读属性（并且它是只读，因为它只有属性 getter ，所以你只能得到它的值）：

  public   string  strDisplayMember 
 {
  get  { return  _cstrdisplayMember; } 
} 

要使它可写，你必须添加一个属性 setter （可以设置其值），类似于这：

  public   string  strDisplayMember 
 {
  get  { return  _cstrdisplayMember; } 
  set  {_cstrdisplayMember =  value ; } 
} 

http：/ /msdn.microsoft.com/en-us/library/w86s7x04.aspx [ ^ ]

---

帮自己一个忙，学习C＃的这些基本元素 - 不要写任何代码直到你理解它们......

你需要一个属性 setter



例如< br $>

  public   string  strDisplayMember 
 {
  get  { return  _cstrdisplayMember; } 
  set  {cstrdisplayMember =  value ;} 
} 

否则该物业是只读的

I have the following code

private readonly string _cstrvalueMember;    //Holds value
private readonly string _cstrdisplayMember;

object obj;
LookupDTO lkpDTOo =(LookupDTO) obj;
if (lkpDTOo.strValueMember == "3")
{
    lkpDTOo.strDisplayMember = "--";
}

But lkpDTOo.strDisplayMember = "--"; here I am getting error like

Error   50  Property or indexer 'XXX.DTO.LookupDTO.strDisplayMember' cannot be assigned to -- it is read only 

Even though I removed readonly and made it public it is not working

解决方案

You have not defined the setter for strDisplayMember in your class.

Try

public string strDisplayMember
{
        get { return _cstrdisplayMember; }
        set { this._cstrdisplayMember = value; }

}

You have a similar problem with strValueMember.

Here is a reference to brush up on Properties[^]

You have to learn what scope and access of a variable are!
You have here a read only property (and it's read only because it have only property getter, so you can only get its value):

public string strDisplayMember
{
  get { return _cstrdisplayMember; }
}

To make it writable you have to add a property setter (which enables to set its value), something like this:

public string strDisplayMember
{
  get { return _cstrdisplayMember; }
  set { _cstrdisplayMember = value; }
}

http://msdn.microsoft.com/en-us/library/w86s7x04.aspx[^]
---
Do yourself a favor and learn these basic elements of C# - do not write any code until you understand them by heart...

You need a property setter

e.g.

public string strDisplayMember
   {
       get { return _cstrdisplayMember; }
       set { cstrdisplayMember = value;}
   }

Otherwise the property is read-only

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