C＃Linq列名作为变量 [英] C# Linq Column Name as variable

问题描述

我有一个表，我想对变量列进行查询。
喜欢：

  private void query（string column，string value）{
 
 using （var db = new myDB（））{
 
 var s1 =（from c in db.Components 
其中（**列** == **值**）
选择新的{c.id，**列**}）; 
} 
} 
  

让我说我要找供应商将如下：

  var s1 =（from c in db.Components 
 where（c.supplier == abc）
 select new {c.id，c.supplier}）; 
  

有没有办法将列名称作为变量传递？

解决方案

这个例子可以是有用的，我猜。

  void BindGridTypeSafe （）
 {
 NorthwindDataContext northwind = new NorthwindDataContext（）; 
 
 var query = from p in northwind.Products 
其中p.CategoryID == 3&&& p.UnitPrice> 3 
 orderby p.SupplierID 
 select p; 
 
 GridView1.DataSource = query; 
 GridView1.DataBind（）; 
} 
 
 void BindGridDynamic（）
 {
 NorthwindDataContext northwind = new NorthwindDataContext（）; 
 
 var query = northwind.Products 
 .Where（CategoryID = 3 AND UnitPrice> 3）
 .OrderBy（SupplierID）; 
 
 GridView1.DataSource = query; 
 GridView1.DataBind（）; 
} 
  

I have a table where I want to make a query on variable columns. Like:

private void query(string column, string value) {

    using (var db = new myDB()) {

        var s1 = (from c in db.Components
                  where (**column** == **value**)
                  select new {c.id, **column**});
    }
}

lets say I want to look for a supplier then it would be like:

var s1 = (from c in db.Components
          where (c.supplier == "abc")
          select new {c.id, c.supplier});

is there a way to pass the column name as variable?

解决方案

This example can be useful i guess.

 void BindGridTypeSafe()
    {
        NorthwindDataContext northwind = new NorthwindDataContext();

        var query = from p in northwind.Products
                    where p.CategoryID == 3 && p.UnitPrice > 3
                    orderby p.SupplierID
                    select p;

        GridView1.DataSource = query;
        GridView1.DataBind();
    }

    void BindGridDynamic()
    {
        NorthwindDataContext northwind = new NorthwindDataContext();

        var query = northwind.Products
                             .Where("CategoryID = 3 AND UnitPrice > 3")
                             .OrderBy("SupplierID");

        GridView1.DataSource = query;
        GridView1.DataBind();
    }

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