C# 在 LinQ Lambda 表达式中连接两列值
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Concatenate two column values in LinQ Lambda Expression
提问by Manas Saha
I am new to LinQ and those lambdas are appearing tricky to me :(
我是 LinQ 的新手，那些 lambdas 对我来说似乎很棘手:(
I have a table where there are two columns. First_Name and Last_name. I am populating a gridview using LinQ.
我有一张有两列的表格。名字和姓氏。我正在使用 LinQ 填充 gridview。
protected void Page_Load(object sender, EventArgs e)
{
myLinQtoSQLClassDataContext objDataContext = new myLinQtoSQLClassDataContext();
var allUserList = from CurrentUser in objDataContext.Users.Where(c => c.Is_Deleted != false)
select new
{
CurrentUser.First_Name,
CurrentUser.Last_Name,
CurrentUser.Email_ID,
CurrentUser.GUID
};
GridView1.DataSource = allUserList;
GridView1.DataBind();
}
I can retrieve the values using LinQ but I want to concatenate the first name and last name with a space in between.
我可以使用 LinQ 检索值，但我想将名字和姓氏连接起来，中间有一个空格。
The equivalent SQL query what I am trying to acchieve would be like this:
我试图实现的等效 SQL 查询将是这样的：
Select First_name + ' ' + Last Name as Username, Email_ID, GUID
From tbl_Users where Is_Deleted != false
How can I achieve this through the lambda expression?
如何通过 lambda 表达式实现这一点？
采纳答案by Mark Byers
You can use string concatenation:
您可以使用字符串连接：
select new
{
Username = CurrentUser.First_Name + " " + CurrentUser.Last_Name,
CurrentUser.Email_ID,
CurrentUser.GUID
};
回答by Mithrandir
Try
尝试
select new
{
FullName = CurrentUser.First_Name + " " + CurrentUser.Last_Name,
CurrentUser.Email_ID,
CurrentUser.GUID
};
回答by Grant Thomas
You should give your anonymous type'keys' (read-only properties):
你应该给你的匿名类型“键”（只读属性）：
select new
{
Name = CurrentUser.First_Name + " " + CurrentUser.Last_Name,
};
And then just concatenate the string on assigning the user name.
然后在分配用户名时连接字符串。
回答by Habib
var allUserList = from CurrentUser in objDataContext.Users.Where(c => c.Is_Deleted != false)
select new
{
Name = CurrentUser.First_Name + " " + CurrentUser.Last_Name,
CurrentUser.Email_ID,
CurrentUser.GUID
};
回答by Parv Sharma
have a look at this CLR Method to Canonical Function Mapping
.Net provides many methods that can be directly mapped to the queries ull have to use one of them to add two strings
so one that u can use is
看看这个CLR Method to Canonical Function Mapping
.Net 提供了许多可以直接映射到查询的方法，你必须使用其中之一来添加两个字符串，
所以你可以使用的是
select new
{
Username = Concat(first_Name,Last_Name),
CurrentUser.Email_ID,
CurrentUser.GUID
};
回答by Bruno
Here's another variation that works and has not been listed:
这是另一个有效但尚未列出的变体：
var allUserList = objDataContext.Users.Where(c => c.Is_Deleted != false).
Select(s => new{First_Name + " " + Last_Name, Email_ID, GUID});
回答by tselvakumars
select new
{
Username = string.Format("{0} {1}", CurrentUser.First_Name, CurrentUser.Last_Name),
CurrentUser.Email_ID,
CurrentUser.GUID
};
