使用system.reflection列出一个类文件 [英] using system.reflection to list a class fileds

问题描述

我需要获取一个列表来存储所有字段-类中的值

i need to get a list to store all fields - values in a class

该类只是我下面粘贴的一些公共 const字符串变量.

the class is just a few of public const string variables as i pasted below.

public class HTDB_Cols
{
    public class TblCustomers
    {
        public const string CustID  = "custID",
               Name  = "name",
         CustType  = "custType",
         AddDate  = "addDate",
         Address  = "address",
         City  = "city",
         Phone  = "phone",
         Cell  = "cell";
    }
}

这是一种返回字符串列表的方法，该方法使我能够使用代表我所有表列名称的字符串列表，尽管由于出现错误，某些东西无法使用此代码

this is a method that returns a list of strings that enables me to have a list of strings representing all my tables columns names , though somthing is not working with this code as i get an error

"非静态字段需要目标".

public class GetClassFields
{

        public static List<string> AsList(string TableName)
        {


                    return typeof(HTDB_Cols).GetNestedTypes()
                    .First(t => String.Compare(t.Name, TableName, true) == 0)
                    .GetFields()
                    .Select(f => f.GetValue(null) as string)
                    .ToList();

        }
}

尝试如下使用它:

foreach (string tblCol in RobCS_212a.Utils.Reflct.GetClassFields.AsList      (DBSchema.HTDB_Tables.TblCustomers))
{
    Response.Write(string.Concat(tblCol, "<br />"));
}

在类型'DBSchema.HTDB_Cols + TblTimeCPAReport'上定义的字段'tbName'不是目标对象上在'DBSchema.HTDB_Cols'类型的字段.

Field 'tbName' defined on type 'DBSchema.HTDB_Cols+TblTimeCPAReport' is not a field on the target object which is of type 'DBSchema.HTDB_Cols'.

推荐答案

您的代码已关闭.有两个问题，都位于linq select方法调用的参数中:

Your code was close. There were two issues, both located in the arguments to your linq select method call:

• 您的类HTDB_Cols是一个非静态类，您尝试检索的字符串值是实例成员.因此，当您尝试从类中拉出实例成员时，必须将类的实例传递给FieldInof.GetValue方法.在下面的代码中，我在变量"instanceOfClass"中创建您的类的实例.您可以在 FieldInfo类

从FieldInfo.GetValue返回的值是一个对象.您必须使用ToString方法或(string)类型转换将其显式转换为字符串.

The value returned from FieldInfo.GetValue is an object. You have to explicitly cast it to a string using the ToString method or the (string) cast.

通过这两个更改，您的方法可以工作.清单如下:

With these two changes your method works. A listing is as follows:

public class GetClassFields
{
    public static List<string> AsList(string tbl)
    {
        var instanceOfClass = new HTDB_Cols();
        return typeof(HTDB_Cols).GetNestedTypes()
                                .First(t => String.Compare(t.Name, tbl, true) == 0)
                                .GetFields()
                                .Select(f => f.GetValue(instanceOfClass).ToString())
                                .ToList<String>();
    }
}

您可以按以下方式调用此函数:

You can call this function as follows:

var fields = GetClassFields.AsList("TblCustomers");

返回所需信息:

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