Playlister (a windows app)

  There are many playlist makers out there; there is Playlist maker, Easy PSP  and then there is good old winamp

  I made my playlist off of winamp, comprising pink Floyd, foo fighters, oasis, and the lot (about a 1000) I wanted to transfer them to my pen drive so I could use it in my car ( I don’t use an iPod), there is no concept of a playlist in my obsolete can audio player, and at first I thought of copying each mp3 file and renaming it according to the order of the playlist … well bad idea… so I thought Ill write an app where I can select an mp3 in the order I want… well no.. so how about reading a winamp playlist, and copying the files and renaming them according to the order of the .m3u playlist (m3u is the extension of a playlist file)

And so I went about writing a windows app that reads an m3u file, reads all the files, gathers their path , copies them to another location and renames them to so they stay in the desired order (the order of the playlist)…. Whew…

   In the process I used some threading, file transfer, renaming constructs.
You can download this from here

And so this is how it looks…

After selecting the playlist, the music files are displayed in a ListBox

   After selecting the transfer path, the transfer button is visible that is based on the copy of move option, select one of these and hit transfer.

you can download the source from here.

Memory leak

     Memory leak is something to be avoided while programming, In .NET, we have the garbage collector, I thought that the System.GC takes care of the left out objects, after going though this informative article : http://www.codeproject.com/Articles/19490/Memory-Leak-Detection-in-NET
how the GC works is ‘GC builds a list of live objects, and then walks through the heap in search of objects which are not present in this list of live objects. After finding out the objects which are not present in this list of live objects, it marks them all as garbage, and starts to compact the memory to remove holes which were created by unreferenced (dead) objects.’ So Any objects with a weak reference are cleared for Garbage collection. The steps GC goes through:

1.    Execution Engine Suspension – The EE is suspended until all managed threads have reached a point in their code execution deemed "safe".
2.    Mark – Objects that don't have roots are marked garbage.
3.    Plan – The GC creates a budget for each generation being collected, and then determines the amount of fragmentation that will exist in the managed heap as a result of a GC collection.
4.    Sweep – Deletes all objects marked for deletion.
5.    Compact – Moves all non-pinned objects that survived the GC to the lower end of the heap.
6.    Execution Engine Restart – Restart the execution of managed threads.

And Unmanaged objects cannot be reclaimed by GC, therefore a ‘finalize’ a necessary there.
Now to the point: If an object is declared using the new keyword… like let’s say
TextBox tb = new TextBox;
Then later in the code the textbox is initialized again like:
tb = (TextBox)Page.FindControl(“TextBox1”);
then does this mean there is a leak?
So I used the GC.GetTotalMemory method to check what happens
Not this may not be the right way to get the memory used. Many in these forum Posts argue that it’s not possible to get the memory used during runtime.
The below console application calculates the memory used before and after a DataTable Object is created, And also if the DataTable is newed again.

namespace memTest
{
    class Program
    {
        static void Main(string[] args)
        {
            long mem = 0;
            mem = GC.GetTotalMemory(true);
            Console.WriteLine(mem.ToString());
            DataTable dt = new DataTable();
            mem = GC.GetTotalMemory(true);
            Console.WriteLine("After Datatabled is newed"+mem.ToString());
            dt = new DataTable();
            mem = GC.GetTotalMemory(true);
            Console.WriteLine("After Datatabled is newed again" + mem.ToString());
            Console.Read();
        }
    }
}

This is the output I got:



 105752 Is at the start, After the DataTable is created It becomes 109960 and after the same DataTable is 'newed' again, the memory remains the same.
And therefore does this mean that the garbage collector recognizes and manages the memory re-allocation?

Your comments please

Exporting a GridView To Excel is simple
Well... but it soms come with some complications
If the gridview has TextBoxes or Checkboxes, you would have to take only the value and put it to a literal control, then export.
And while exporting; If you are using the UpdatePanel, it means you cannot have the export button within the panel,
as this works against the response object to create the excel file, you would have to add a postback trigger to the button.

the .aspx
<asp:UpdatePanel runat=server ID=updPnl>
<ContentTemplate>
<table>
<tr><td><asp:ImageButton ID="LinkButtonExcel"  runat="server" ImageUrl="~images/ex.jpg"
        ToolTip="Click to export contents of grid to Excel."
        onclick="LinkButtonExcel_Click" CausesValidation="false"></asp:ImageButton>
</td></tr>
<tr><td>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="True" ></asp:GridView>
<td><tr>
</table>
 </ContentTemplate></UpdatePanel>

the codebehind

.cs
protected void LinkButtonExcel_Click(object sender, ImageClickEventArgs e)
        {
            try
            {
                GridView1.AllowPaging = false;
                bindRpt(); // this method binds the gridview
                GenerateExcel(GridView1);
            }
            catch
            {
                Page.ClientScript.RegisterStartupScript(this.GetType(), "", "alert('Could not Export to excel, please try again later );", true);
            }
        }


public void GenerateExcel(GridView grdSource)
        {

            StringBuilder sbDocBody = new StringBuilder();
            try
            {
                // Declare Styles
                sbDocBody.Append("<style>");
                sbDocBody.Append(".Header {  background-color:Navy; color:#ffffff; font-weight:bold;font-family:Verdana; font-size:12px;}");
                sbDocBody.Append("</style>");
                //
                StringBuilder sbContent = new StringBuilder();

                sbDocBody.Append("<br><table align=\"center\" cellpadding=0 cellspacing=0 border=1>");

                if (grdSource.Rows.Count > 0)
                {
                    for (int i = 0; i < grdSource.Columns.Count - 1; i++)
                    {
                        sbDocBody.Append("<td class=\"Header\" width=\"120\">" + grdSource.Columns[i].HeaderText + "</td>");
                    }
                    sbDocBody.Append("</tr>");
                    // Add Data Rows
                    for (int i = 0; i < grdSource.Rows.Count; i++)
                    {
                        sbDocBody.Append("<tr>");
                        for (int j = 0; j < grdSource.Columns.Count - 1; j++)
                        {
                            if (grdSource.Rows[i].Cells[j].Controls.Count == 0)
                            {
                                sbDocBody.Append("<td class=\"Content\">" + grdSource.Rows[i].Cells[j].Text + "</td>");
                            }
                            else
                            {
                                if (grdSource.Rows[i].Cells[j].Controls[1].ToString() == "System.Web.UI.WebControls.LinkButton")
                                {
                                    LinkButton lnkBtn = (LinkButton)grdSource.Rows[i].Cells[j].Controls[1];
                                    sbDocBody.Append("<td class=\"Content\">" + lnkBtn.Text + "</td>");
                                }
                                else if (grdSource.Rows[i].Cells[j].Controls[1].ToString() == "System.Web.UI.WebControls.Label")
                                {
                                    Label lblData = (Label)grdSource.Rows[i].Cells[j].Controls[1];
                                    sbDocBody.Append("<td class=\"Content\">" + lblData.Text + "</td>");
                                }
                                else
                                if (grdSource.Rows[i].Cells[j].Controls[1].ToString() == "System.Web.UI.WebControls.TextBox")
                                {
                                    TextBox tb = (TextBox)grdSource.Rows[i].Cells[j].Controls[1];
                                    sbDocBody.Append("<td class=\"Content\">" + tb.Text + "</td>");
                                }
                            }
                        }
                        sbDocBody.Append("</tr>");
                    }
                    sbDocBody.Append("</table>");
                 }
                //
                HttpContext.Current.Response.Clear();
                HttpContext.Current.Response.Buffer = true;
                //
                HttpContext.Current.Response.AppendHeader("Content-Type", "application/ms-excel");
                HttpContext.Current.Response.AppendHeader("Content-disposition", "attachment; filename=BiasReport-" + DateTime.Now.ToLongDateString() + ".xls");
                HttpContext.Current.Response.Write(sbDocBody.ToString());
                HttpContext.Current.Response.End();
            }
            catch (Exception ex)
            {
                // Ignore
            }
        }