列表<；T>；需要'；1'；类型参数

本文关键字：类型参数 需要 lt 列表 gt | 更新日期: 2023-09-27 18:25:36

我正在阅读这本书

http://hookedonlinq.com/LINQBook.ashx

然而，当我尝试实现这个代码

public class Contact
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Email { get; set; }
    public string Phone { get; set; }
    public DateTime DateOfBirth { get; set; }
    public string State { get; set; }
    public static List SampleData()
    {
        return new List { 
            new Contact { FirstName = "Barney", LastName = "Gottshall", DateOfBirth = new DateTime(1945,10,19), Phone = "885 983 8858", Email = "bgottshall@aspiring–technology.com", State = "CA" }, 
            new Contact { FirstName = "Armando", LastName = "Valdes", DateOfBirth = new DateTime(1973,12,09), Phone = "848 553 8487", Email = "val1@aspiring–technology.com", State = "WA" }, 
            new Contact { FirstName = "Adam", LastName = "Gauwain", DateOfBirth = new DateTime(1959,10,03), Phone = "115 999 1154", Email = "adamg@aspiring–technology.com", State = "AK" }, 
            new Contact { FirstName = "Jeffery", LastName = "Deane", DateOfBirth = new DateTime(1950,12,16), Phone = "677 602 6774", Email = "jeff.deane@aspiring–technology.com", State = "CA" }, 
            new Contact { FirstName = "Collin", LastName = "Zeeman", DateOfBirth = new DateTime(1935,02,10), Phone = "603 303 6030", Email = "czeeman@aspiring–technology.com", State = "FL" }, 
            new Contact { FirstName = "Stewart", LastName = "Kagel", DateOfBirth = new DateTime(1950,02,20), Phone = "546 607 5462", Email = "kagels@aspiring–technology.com", State = "WA" }, 
            new Contact { FirstName = "Chance", LastName = "Lard", DateOfBirth = new DateTime(1951,10,21), Phone = "278 918 2789", Email = "lard@aspiring–technology.com", State = "WA" }, 
            new Contact { FirstName = "Blaine", LastName = "Reifsteck", DateOfBirth = new DateTime(1946,05,18), Phone = "715 920 7157", Email = "blaine@aspiring–technology.com", State = "TX" }, 
            new Contact { FirstName = "Mack", LastName = "Kamph", DateOfBirth = new DateTime(1977,09,17), Phone = "364 202 3644", Email = "mack.kamph@aspiring–technology.com", State = "TX" }, 
            new Contact { FirstName = "Ariel", LastName = "Hazelgrove", DateOfBirth = new DateTime(1922,05,23), Phone = "165 737 1656", Email = "arielh@aspiring–technology.com", State = "OR" } };
    }
}

我得到错误System.Collections.Generic.List需要"1"类型参数我知道该列表需要定义为例如

List<string>

或

List<int>

但无法确定列表应该是什么。有人能帮忙吗？

感谢

列表<；T>；需要'；1'；类型参数

public static List<Contact> SampleData()


return new List<Contact> { ....

因为您放入列表的对象是Contact的

思考泛型的一个简单方法是使用单词"of"，例如List<Contact>与说"联系人列表"

相同

您忘记指定列表的类型。

  public static List<Contact> SampleData()
    {
        return new List<Contact> { 
            new Contact { FirstName = "Barney", LastName = "Gottshall", DateOfBirth = new DateTime(1945,10,19), Phone = "885 983 8858", Email = "bgottshall@aspiring–technology.com", State = "CA" }, 
            new Contact { FirstName = "Armando", LastName = "Valdes", DateOfBirth = new DateTime(1973,12,09), Phone = "848 553 8487", Email = "val1@aspiring–technology.com", State = "WA" }, 
            new Contact { FirstName = "Adam", LastName = "Gauwain", DateOfBirth = new DateTime(1959,10,03), Phone = "115 999 1154", Email = "adamg@aspiring–technology.com", State = "AK" }, 
            new Contact { FirstName = "Jeffery", LastName = "Deane", DateOfBirth = new DateTime(1950,12,16), Phone = "677 602 6774", Email = "jeff.deane@aspiring–technology.com", State = "CA" }, 
            new Contact { FirstName = "Collin", LastName = "Zeeman", DateOfBirth = new DateTime(1935,02,10), Phone = "603 303 6030", Email = "czeeman@aspiring–technology.com", State = "FL" }, 
            new Contact { FirstName = "Stewart", LastName = "Kagel", DateOfBirth = new DateTime(1950,02,20), Phone = "546 607 5462", Email = "kagels@aspiring–technology.com", State = "WA" }, 
            new Contact { FirstName = "Chance", LastName = "Lard", DateOfBirth = new DateTime(1951,10,21), Phone = "278 918 2789", Email = "lard@aspiring–technology.com", State = "WA" }, 
            new Contact { FirstName = "Blaine", LastName = "Reifsteck", DateOfBirth = new DateTime(1946,05,18), Phone = "715 920 7157", Email = "blaine@aspiring–technology.com", State = "TX" }, 
            new Contact { FirstName = "Mack", LastName = "Kamph", DateOfBirth = new DateTime(1977,09,17), Phone = "364 202 3644", Email = "mack.kamph@aspiring–technology.com", State = "TX" }, 
            new Contact { FirstName = "Ariel", LastName = "Hazelgrove", DateOfBirth = new DateTime(1922,05,23), Phone = "165 737 1656", Email = "arielh@aspiring–technology.com", State = "OR" } };
    }
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