server.mappath

suppose your requirement is upload the song or images in database ,or in u r project"images" or "Audio" folder u want to saved then u used FileUpload.Saveas(Server.Mappath("newfolder"+filename)) for u r details understanding do example follow.
{

                                Audio Song Uploading

In this Article we see how to upload Audio or MP3 song in Database and also Aplication folder like Audio.This is simple code useful for Developer

So lets see  step by step procedure

 

Step 1) Take textbox and fileupload control and Button and lable

 

Step 2)Create table like

{

CREATE TABLE [dbo].[Audio](

      [id] [int] NOT NULL,

      [song] [varchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,

 CONSTRAINT [PK_Audio] PRIMARY KEY CLUSTERED

(

}

 

 

 

Step 3)Now write stored procedure

{

ALTER procedure Sp_Audio(@id int,@song varchar(50))

As

Begin

insert into Audio(id,song)values(@id,@song)

end

}

}

 

Step 4)Now double click on Button and write code

{

SqlConnection cn = new SqlConnection("Give Path");

 

        SqlCommand cmd = new SqlCommand();

        cmd.Connection = cn;

        cn.Open();

        cmd.CommandText = "Sp_Audio";

        cmd.CommandType = CommandType.StoredProcedure;

 

        cmd.Parameters.AddWithValue("@id", TextBox1.Text);

        cmd.Parameters.AddWithValue("@song", FileUpload1.FileName);

         int i=cmd.ExecuteNonQuery();

 

        if (FileUpload1.HasFile)

        {

            string fname = FileUpload1.FileName.ToString();

            string folderpath = "~/Audio";

            string path = HttpContext.Current.Server.MapPath(folderpath);

 

            FileUpload1.PostedFile.SaveAs(path + "\\" + fname);

            Label1.Text = "file uploaded successfully";

        }

    }

}

Step 5)Now Run Application

}