Question

我想在API端的控制器类中编写一个方法，以返回所有列名的列表。该方法将是什么样子，它将返回什么？以及如何在客户端检索此“列表”？

private CoreGradingDBEntities db = new CoreGradingDBEntities();

// GET: api/
public IQueryable<Account> GetAccounts()
{
  return db.Accounts;
}


//Get field names
//What is the response type
public IHttpActionResult GetFieldNames()
{
  //Query goes here, gets executed and returns all column names?
}

// GET: api/Accounts/5
[ResponseType(typeof(Account))]
public IHttpActionResult GetAccount(string id)
{
    Account account = db.Accounts.Find(id);
    if (account == null)
    {
         return NotFound();
    }
    return Ok(account);
}

一个查询，该查询返回我想执行并作为HTTP响应获取的列名。

SELECT COLUMN_NAME

FROM INFORMATION_SCHEMA.COLUMNS

WHERE TABLE_NAME = 'Account'

ORDER BY ORDINAL_POSITION

Answer 1

有两种方法可以完成此任务：

第一个是使用。NET data provider或dding this query to your EF model直接从代码中调用SQL查询。

另一个是访问use reflection的帐户类型属性：

typeof(Account).GetProperties(BindingFlags.Public|BindingFlags.Instance)

Answer 2

答案

因此，我添加了一个新的控制器类，它是一个不依赖于数据库的自定义类。我还向WebApiConfig.cs文件添加了一条新路由。以及新的“模板”类。这就是我所拥有的。

WebApiConfig.cs（添加的代码）

请注意，该ID是必填项。我将使用它作为希望从中获取字段名称的表名。

config.Routes.MapHttpRoute(
name: "FieldValues",
routeTemplate: "api/FieldValues/id",
defaults: new { controller = "FieldValues"}
);

FieldValues.cs（新类）

    public class FieldValues
    {
        public string COLUMN_NAME { get; set; } //this "variables" name is same as in query. Note: if the set is not present nulls would be returned
    }

FieldValuesController.cs（新控制器）

    public class FieldValuesController : ApiController
    {
        private CoreGradingDBEntities db = new CoreGradingDBEntities();

        [Route("api/FieldValues/id")]
        public IList<FieldValues> Get(string id)
        {
            var response = db.Database.SqlQuery<FieldValues>("SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = '" + id + "' ORDER BY ORDINAL_POSITION").ToList();
            return response;
        }
    }

JSON响应

[{"$id":"1","COLUMN_NAME":"ID"},{"$id":"2","COLUMN_NAME":"DepartmentID"},{"$id":"3","COLUMN_NAME":"PermissionID"},{"$id":"4","COLUMN_NAME":"Username"},{"$id":"5","COLUMN_NAME":"PasswordHash"},{"$id":"6","COLUMN_NAME":"PasswordResetToken"},{"$id":"7","COLUMN_NAME":"TokenValid"},{"$id":"8","COLUMN_NAME":"Email"},{"$id":"9","COLUMN_NAME":"EmailConfirmed"},{"$id":"10","COLUMN_NAME":"PhoneNumber"},{"$id":"11","COLUMN_NAME":"PhoneNumberConfirmed"},{"$id":"12","COLUMN_NAME":"TwoFactorEnabled"},{"$id":"13","COLUMN_NAME":"AccessFailedCount"},{"$id":"14","COLUMN_NAME":"LocoutEndDate"},{"$id":"15","COLUMN_NAME":"LockoutEnabled"}]

获取请求

api/FieldValues/id?id={id}

使用

api/FieldValues/id?id=Account //the 'Account' can be replaced by your table name you wish to get the values from

如何获取数据库表中列名称的JSON响应

2 个答案:

答案