如何在c#中返回一个列表? [英] how to return a list in c#?
问题描述
列表< sfdclistinfo> IstsfdcInfo = new 列表< sfdclistinfo>();
i需要返回列表,如果它包含数据并将它们绑定到datagridview
[edit]已添加代码块 - OriginalGriff [/ edit]
第一:
列表是泛型类型。换句话说,它们必须是某物的列表。你需要告诉它 是什么:
// < span class =code-comment> List< t> list = new List< t>()其中T是Type。
List< int> intList = new List< int>(); // a整数列表
intList.Add( 1 跨度>); // 将整数添加到列表中
intList.Add( 256 跨度>);
if (intList.Any()) // linq方式说intList.Count()> 0
Console.WriteLine(intList.Count());
// out:> 2
列表类型可以是任何类型。我在这里使用了一个原语,但它们通常用于存储复杂和用户定义的类型。
List的替代方案包括但不限于:
// 数组
int [] intArray = new int [ 2 ]; // 创建一个int数组,但它有一个固定的大小(2)。
< span class =code-comment> // Dictionary
Dictionary< int,string> = new 字典< int,string>(); // 用法非常不同。此类型存储一个键(int)用于访问它的值(字符串)。
所有这些集合都是通用的,如果没有用类型指定就无法实现(好的,所以Arrays有点不一样但仍然必须打字)。
有关泛型的更多信息,请看这个链接
在ASP.NET中使用C#的泛型示例 [ ^ ]
该列表不包含数据 - 它只是创建一个新的空列表。
如果你想向它添加项目(来自某些来源)那么使用DataGridView非常非常容易:
public class ProdTotalSales
{
public string 文字{ get ; set ; }
public int 值{ get 跨度>; set ; }
私有 字符串隐藏{获取跨度>; set ; }
public ProdTotalSales( string s, string h, int i)
{
Text = s;
隐藏= h;
价值= i;
}
}
ProdTotalSales p1 = new ProdTotalSales( P1, p1 hidden, 1 );
ProdTotalSales p2 = new ProdTotalSales( P2 , p2 hidden, 2 跨度>);
List< prodtotalsales> list = new List< prodtotalsales>(){p1,p2};
myDataGridView.DataSource = list;
将为您提供一个包含两列的DataGridView(一个用于类中的每个公共属性)和两行(一个用于每个类的实例)列表)。
List<sfdclistinfo> IstsfdcInfo = new List<sfdclistinfo>();
i need to return the list if it contains data and bind them to datagridview
[edit]Code block added - OriginalGriff[/edit]
First:
List are a generic type. In other words they must be a list of something. You need to tell it what that something is:
//List<t> list = new List<t>() where T is a Type. List<int> intList = new List<int>(); //a List of integers intList.Add(1); // add integer to the list intList.Add(256); if(intList.Any()) // a linq way of saying intList.Count()>0 Console.WriteLine(intList.Count()); //out:> 2
The list Type can be any type. I used a primitive here but they are often used for storing complex and user defined types.
Alternatives to List include, but are not limited to:
//Array int[] intArray = new int[2]; // creates an array of ints but it has a fixed size (2). //Dictionary Dictionary<int,string> = new Dictionary<int,string>(); //very different usage.This type stores a key(int) that is used to access its value(string).
All of these collections are generic and cannot be instanciated without being specified with a type (ok, so Arrays are a little different but the still must be typed).
For more information on generics please see this link
An Example of Generics Using C# in ASP.NET[^]
That list won't contain data - it just creates a new, empty list.
If you want to add items to it (from some source) then it's very, very easy to use it with a DataGridView:
public class ProdTotalSales { public string Text { get; set; } public int Value { get; set; } private string Hidden { get; set; } public ProdTotalSales(string s, string h, int i) { Text = s; Hidden = h; Value = i; } }
ProdTotalSales p1 = new ProdTotalSales("P1", "p1 hidden", 1); ProdTotalSales p2 = new ProdTotalSales("P2", "p2 hidden", 2); List<prodtotalsales> list = new List<prodtotalsales>() { p1, p2 }; myDataGridView.DataSource = list;
Will give you a DataGridView with two columns (one for each public property in the class) and two rows (one for each instance of the class in the List).
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