C# 6.0 内插字符串(Interpolated Strings )的使用方法

var city = \"London\";

using (var context = CreateContext())
{
 context.Customers
  .FromSql($@\"
   SELECT *
   FROM Customers
   WHERE City = {city}\")
  .ToArray();
}

@p0=\'London\' (Size = 4000)

SELECT *
FROM Customers
WHERE City = @p0

var name = \"world\";
Console.WriteLine($\"hello {name}\");

var name = \"world\";
string str1 = $\"hello {name}\"; //等于 var str1 = $\"hello {name}\";
IFormattable str2 = $\"hello {name}\";
FormattableString str3 = $\"hello {name}\";

var name = \"world\";
string str1 = string.Format(\"hello {0}\",name); //等于 var str1 = $\"hello {name}\";
IFormattable str2 = FormattableStringFactory.Create(\"hello {0}\",name);
FormattableString str3 = FormattableStringFactory.Create(\"hello {0}\",name);

var name = \"world\";
FormattableString fmtString = $\"hello {name}\";
Console.WriteLine(fmtString.ArgumentCount); //1
Console.WriteLine(fmtString.Format); //hello {0}
foreach (var arg in fmtString.GetArguments())
{
 Console.WriteLine(arg); //world
 Console.WriteLine(arg.GetType()); //System.String
}

var city = \"London\";

using (var context = CreateContext())
{
 //方法一，非参数化
 var sql = $\" SELECT * FROM Customers WHERE City = {city}\";
 context.Customers.FromSql(sql).ToArray();

 //方法二，参数化
 context.Customers.FromSql($\" SELECT * FROM Customers WHERE City = {city}\").ToArray();

 //方法三，参数化
 FormattableString fsql = $\" SELECT * FROM Customers WHERE City = {city}\";
 context.Customers.FromSql(fsql).ToArray();

 //方法四，非参数化
 var sql = \" SELECT * FROM Customers WHERE City = @p0\";
 context.Customers.FromSql(sql, city).ToArray();

}