Improved SaveAs() Method on the FileUpload Control

This extension handles things such as duplicate filenames and on-the-fly directory creation

Previously I showed how to save multiple files of the same name which I have used many times, so much in fact that I figured I would make a universal drop-in extension for it.

This new extension improves on the SaveAs() method in a few ways:
  • If a directory doesn't yet exist, it will be made
  • If a file already exists with the same file name, an incremented tag will be added: abc.pdf, abc[1].pdf, abc[2].pdf, etc.
  • It returns the name the file was saved with

There are two ways to call it:
  • FileUploadControl.SaveAsNoOverwrite() :: will save to the current directory with the 'FileName' property of the 'FileUpload'
  • FileUploadControl.SaveAsNoOverwrite(path) :: where 'path' is the path to save to

Here is the code:
public static string SaveAsNoOverwrite(this FileUpload up, string saveas)
{
  string[] split = saveas.Split(new char[] { '\\', '/' }, StringSplitOptions.RemoveEmptyEntries);

  string directory = string.Empty;
  for (int i = 0; i < split.Length - 1; i++) directory += split[i] + "\\";

  string filename = split[split.Length - 1];

  //saves to current directory if only filename is specified
  if (string.IsNullOrEmpty(directory)) directory = HttpContext.Current.Server.MapPath(".") + "\\";
  //creates directory if it does not exist
  else if (!Directory.Exists(directory)) Directory.CreateDirectory(directory);

  string[] fileNameSplit = filename.Split(new char[] { '.' });
  string ext = "." + fileNameSplit[fileNameSplit.Count() - 1];
  string prefix = filename.Substring(0, filename.Length - ext.Length);

  int count = 1;
  // if the files already exists, this will append a [x] where x is 0+(number of files existing with the same name)
  while (File.Exists(directory + filename))
  {
    filename = prefix + "[" + count.ToString() + "]" + ext;
    count++;
  }
  up.SaveAs(directory + filename);
  return filename;
}

public static string SaveAsNoOverwrite(this FileUpload up)
{
  return up.SaveAsNoOverwrite(up.FileName);
}

Getting started with Linq-To-Entities tutorial

The transition from Linq-to-SQL to .Net's Entities framework is incredibly simple

In my humble opinion, Linq is easily the greatest thing .Net has come out with in the past few years, and along with it, Linq-to-SQL (L2S) was a godsend. Being quick to hop on the L2S bandwagon, I quickly became a huge fan of the framework, it is amazing easy and useful. That being as it is, I was quite disappointed when I heard that Linq-to-SQL was no longer going to be advanced at all. Now, it is surely not dead, it is still very usable and effective at what it does, but I like to stay with frameworks that will be actively advanced and fbug-fixed. So I decided to make the jump to Linq-to-Entities (L2E), and it was suprisingly simple.

This guide should be a good starting point for anyone whether or not they are familiar with L2S, and a quick 'jumping guide' to L2S developers. Here's how to get started:

Make your ADO.NET Entity Data Model (.edmx file)

This is comparable to the .dbml file that you made with L2S.
  • Right click on your App_Code folder and select New Item
  • Select ADO.NET Entity Data Model and name it (I left the default Model.edmx for the example)
  • Choose Generate from database and click Next
  • Choose your database from the dropdown and choose the name to save the ConnectionString as and click Next
  • Choose all the things you want included, I just chose tables, but you may want to include views and SPs if you have them
  • *Be sure to remember the Model Namespace you choose for your .edmx (I will use DatabaseModel for the example) - click Finish

Now it will take a moment to run through and produce your .edmx; when it is done you will see a nice little representation of your tables reminiscent of the .dbml display in L2S:

Access your .edmx

Now we simply access the .edmx much like we did with L2S. You must remember to add Using DatabaseModel (or whatever your namespace was) to the code where you are using it. Now we will make a DatabaseModel object and use it to add a 'product' to the database. First, you need to make your Entity Access Object:
DatabaseEntities db = new DatabaseEntities();

Then you can use it to enter an object:
products p = new products();
p.product_name = "Word Processing Software";
p.price = 99;
p.stock = 100;
db.AddToproducts(p);
db.SaveChanges();

Once again, if you are familiar with L2S, this is almost the same exact thing! If you are new, this is very straight-forward and should be easy to understand:
  • Make an object of a type inside your database
  • Fill the object up with data
  • Put it into the database
  • Save the changes

Now L2E one-ups L2S and makes data entry even easier, this will accomplish the same as above:
db.AddToproducts(products.Createproducts(0, "Accounting Software", 300, 125));
db.SaveChanges();

Notice that the 'product_id' is entered as '0', that is because it is auto-incrementing, so it doesn't matter what I put there, it will be ignored. Now I don't know about you, but that little bit there will save me hundreds of lines of code! I am starting to like L2E already!

Display your data

Now that we have put a few objects in to the database, we can go and check it out. Later we will dig in with code, but first we will use a LinqDatasource/GridView:
  • Drag a LinqDataSource (LDS) on to the page and click Configure Data Source from the little square on the upper right of the LDS
  • Choose your Object Model and click Next
  • Choose your table and click Finished
  • Drag a GridView (GV) on to your page
  • In the GV option box, choose your datasource from the dropdown

now just view your page:

Modify Data

Now that we have seen how to put in data, we will modify some; once again, L2E makes it trivially simple:
products edit = (from p in db.products where p.product_id == 2 select p).First();
edit.product_name = "Account Software v2";
db.SaveChanges();

The Linq statement is EXACTLY like it would be in L2S, and just like in L2S, you can shorten up this with some Lambda integration; this will accomplish the same thing:
db.products.First(p => p.product_id == 2).product_name = "Accounting Software v2.1";
db.SaveChanges();

Deleting Items
Now that we have seen Insert and Update, the next logical step is Delete, and it is just as easy. Let us delete the 'Word Processing Software' frorm the table:
products del = (from p in db.products where p.product_id == 1 select p).First();
db.DeleteObject(del);
db.SaveChanges();

And the same exact thing shorthand with Lambdas:
db.DeleteObject(db.products.First(p => p.product_id == 1));
db.SaveChanges();

Once again, I have to say I like the approach that L2E takes of that of L2S, as it is not necessary to specify which table to delete from, as an object can only be deleted frorm the table that it is in.

Using your database relations

As in L2S, L2E takes great advantage of well designed databases and relations. If you noticed up above, the two tables in my database have a 1 to many relation frorm product to reviews. Each element in the 'reviews' table is required to relate to an element in the 'products' table (column 'product_id'). Let's fill the DB with a few more products and some reviews; a lot is going to go on here:
products p1 = db.products.First(p => p.product_id == 2);
products p2 = products.Createproducts(0, "Strategy Game", 49, 99);
products p3 = products.Createproducts(0, "Sports Game", 39, 99);
db.AddToproducts(p2);
db.AddToproducts(p3);

reviews r1_1 = reviews.Createreviews(0, "Much Improved", "this is a much better version", "Bill Brasky");
r1_1.productsReference.Value = p1;
reviews r2_1 = reviews.Createreviews(0, "Terrible", "worthless", "Dirk Digler");
r2_1.productsReference.Value = p2;
reviews r3_1 = reviews.Createreviews(0, "Great Game", "very tough AI", "Wonderboy");
r3_1.productsReference.Value = p3;
reviews r3_2 = reviews.Createreviews(0, "Very Fun", "the Bears rule", "Mike Ditka");
r3_2.productsReference.Value = p3;

db.AddToreviews(r1_1);
db.AddToreviews(r2_1);
db.AddToreviews(r3_1);
db.AddToreviews(r3_2);

db.SaveChanges();

Now to explain what just happened:
  • The first line gets an object of type products where product_id == 2 (this is 'Accounting Software v2.1')
  • The next two lines create new products
  • The next two submit those into the database

Now we have a total of 3 objects in the 'products' table and none in the 'review' table, that is where the next 8 lines come in. If you break up those 8 lines into pairs of two, you can see they are all the same thing really:
  • Make a new object of type reviews
  • Assign its foreign key reference to a products object

Since the database requires a relation between these two tables, you must be sure to set the reference. The last lines just submit everything and commit them to the database.

Now that that is in there, you can use the real power of relations in L2E. Once again, it is almost the same as L2S:
foreach (products p in (from _p in db.products select _p))
{
  Response.Write("<h3>" + p.product_name + " - $" + p.price + "</h3>");
  Response.Write("<b>Reviews:</b><div style='border:1px solid navy;padding:5px;'>");
  p.reviews.Load(); // this loads all the reviews that relate to the product p
  foreach (reviews r in p.reviews)
    Response.Write("<b>" + r.title + " - " + r.reviewer + "</b><br />" + r.review + "<br />");
  Response.Write("</div><br />");
}

And this is what you get:
Yes, I know I used the ugly 'Response.Write', and the output is hideous... but this is just a demo people! As you can see, it is incredibly easy to iterate through all of the reviews of a products, this big difference being that you need to call the .Load() method or they will not be populated. Now this is both a blessing and a curse; this is very efficient as it only loads the related objects if need be, but... it is soemthing that is easy to forget and may leave you scratching your head. I think I like it.

Now relations also work the other way as well. Say you have a reviews object, and you want to know the price of the products it is related to. No need to actually look up the products object, you just call the relation:
reviews r = db.reviews.First(_r => _r.review_id == 3);
r.productsReference.Load();
Response.Write("Price: $" + r.productsReference.Value.price.ToString());

Once again, notice that you have to Load() the reference, or you will get nothing.

Now that should get you started. Like I said, if you are familiar with L2S, this transition should be no problem, and if you are new to this whole Linq arena, this should be simple to pick up. This new ADO is getting more and more impressive the more MS works on it. I can't even imagine goging back to the old methods...

Simplify setting your DropDownLists to a specific value

An extension to quickly and easily set your DropDowns while avoiding errors

Sometimes you want to set your DropDownList to a value that may or may *not* be in the DropDownList, but setting that can be a bit tricky as it will often error out. This extension will avoid that and give you a simple way to set your DropDownLists wihtout all the extra code:
public static void Set(this DropDownList ddl, string findByVal)
{ // attempts to set a DDL to the 'findByVal'
  try { ddl.SelectedIndex = ddl.Items.IndexOf(ddl.Items.FindByValue(findByVal)); }
  catch { };
}

Now just call it from your DropDownList:
SomeDropDownList.Set("Some String Value");

And it will attempt to set your DropDownList to that value, but *not* error out if it doesn't exist.

Simple Dynamic Sorting Headers for GridView using indication arrows

A simple centralized way to make a nice flipping indicator (arrow) of which way you are sorting on a GridView

When sorting with gridviews, it is nice to have an indicator of which direction you are sorting on which field like the use at Yahoo! Autos. To copy this idea, I simply made 3 Css classes 'sort', which is a base class with no backgorund image, 'up' which has an up arrow, and 'down' which has a down arrow in it. I made sure to put the backgorund image in just once, and push the text away so it can show through. Also, since these will be applied to the Header element of the GridView, you have to make sure you declase '.class a':
.up a, .down a, .sort a { display:block; padding:0 4px 0 15px; }
.up a, .down a { color:#8F5F00; }
.sort a:hover { background:#ffcc66; }
.up a { background:url(../images/up.gif) left no-repeat; }
.up a:hover { background:url(../images/up.gif) left no-repeat #ffcc66; }
.down a { background:url(../images/down.gif) left no-repeat }
.down a:hover { background:url(../images/down.gif) left no-repeat #ffcc66; }

Now, I made a function in a helper Class that will take in the same arguments that a GridView Sorting event throws, that way the transition will be easy.
// This is used to flip the sorting arrow up/down
// Base Css class is 'sort', the Ascending Css Class is 'up' and Descending is 'down'
public static void GVSort(object sender, GridViewSortEventArgs e)
{ // call on sort and sets the sorted field to the proper Css Class, while setting all others to the base class
  string BASE = "sort";
  string UP = "up";
  string DOWN = "down";
  GridView g = (GridView)sender;
  for (int i = 0; i < g.Columns.Count; i++)
  {
    var c = g.Columns[i];
    c.HeaderStyle.CssClass = c.HeaderStyle.CssClass.Replace(UP, BASE).Replace(DOWN, BASE);
    if (c.SortExpression.Equals(e.SortExpression))
    {
      c.HeaderStyle.CssClass =
        e.SortDirection.Equals(System.Web.UI.WebControls.SortDirection.Ascending) ?
          c.HeaderStyle.CssClass.Replace(BASE, UP).Replace(DOWN, UP) :
          c.HeaderStyle.CssClass.Replace(BASE, DOWN).Replace(UP, DOWN);
    }
  }
}

Now say I had this in a class utils.cs I would just call it one the GridView Sorting event:
protected void gv_Sorting(object sender, GridViewSortEventArgs e)
{
  sao.GVSort(sender, e);
}

And there you have it! You can call that from every Gridview in your application that you want to look similar - code only once!

Change column name in a MSSQL table

For some reason, MS does not have a built in command for this?


Not sure why this is as competeing technologies like Oracle and MySQL do, but there is a stored procedure that will get you where you are going:
EXEC sp_rename 'TABLENAME.OLD_COLUMNNAME', 'NEW_COLUMNAME', 'COLUMN';

Just replace TABLENAME.OLD_COLUMNNAME and NEW_COLUMNNAME with your new values.

Convert DateTime to Military Time

Good ol' military time


To continue on my posts about extend existing classes (I have been doing these a lot at my new job), here is a simple extension to make DateTime.ToMilitaryString() to output a military time such as: 21 DEC 08 : 16:22:34 - it's very simple actually:
public static string ToMilitaryString(this DateTime dt)
{
  string time = dt.ToString("dd MMM yy : hh:mm:ss");
  return time.Substring(0,12) + dt.Hour + time.Substring(14,6);
}

Insert commas into your currency values

Make your currency more readable


Last post I showed how to limit the decimal places of a double and decimal, but when you display a long number that represents currency, this is not what you want your user to see: $1123443322.25, you want it nicely formatted like this: $1,123,443,322.25 - much easier to read!

To do that, just extend an existing class, I am going to use string, but you could easily make this into a number as well.
public static string ToMoney(this string s)
{
  int period = s.IndexOf(".");
  if (period == -1) return s;
  else
  {
    string right_side = s.Substring(period, s.Length - period);
    string left_side = s.Substring(0, period);
    while (left_side.Length > 3)
    {
      right_side = "," + left_side.Substring(left_side.Length - 3, 3) + right_side;
      left_side = left_side.Substring(0, left_side.Length - 3);
    }
    return left_side + right_side;
  }
}

Now just use this as you would any other method of string:
string long_money = 1123443322.25;
string money = long_money.ToMoney();

money now equals 1,123,443,322.25. This would be easy to change in to working with double, int, etc.

UPDATE - 2009-01-20

Or just forego all my silly programming and use the built in function Howard pointed out (that I didn't know :P):
value.ToString("c")

//Or if the currency symbol isn't required use:
value.ToString("#,##0.00")

Thanks Howard... I feel like a fool; isn't the internet great?

A simple way to add a 'View All' sort option to your DataSource in Asp.Net

Just use a little SQL trick to simplify and add usability to your DataSource

Often times I have integer fields in my database that serve as categories. These categories are very helpful when sorting for the users, butit is sometimes tough to write a simple, one-line query to output ALL of them; I figured an extremely simple way to do this. This may be a little hard to explain, but it is very useful.

For this example, I am going to use a LINQDataSource

<asp:LinqDataSource ID="ldsCases" runat="server" ContextTypeName="dbDataContext" TableName="Cases" Where="Category == @Category">

   <WhereParameters>

     <asp:SessionParameter Name="Category" SessionField="Cat" Type="Int32" />

   </WhereParameters>

</asp:LinqDataSource>


This is using a Session variable to work with the DataSource which will be set the the integer value that corresponds to the category I want to find. Now this will work just fine if we are trying to just look at a single category, but what if we want to look at all of them? It is really quite simple, now, just add one more OR (||) statement to our SQL and set the Session variable to 0 any time we want to call everything:

<asp:LinqDataSource ID="ldsCases" runat="server" ContextTypeName="dbDataContext" TableName="Cases" Where="(Category == @Category) || ((Category * @Category) == 0)">

   <WhereParameters>

     <asp:SessionParameter Name="Category" SessionField="Cat" Type="Int32" />

   </WhereParameters>

</asp:LinqDataSource>

Back from Hiatus

Back to work...

Just got back from a nearly month long Hiatus so I should be updating again soon. Working 7 days a week at 12 hours a day should give me plenty of things to write about. Iraq is beautiful this time of year :)

No applicable method 'Contains' exists in type 'String'

Solution for this annoying error while using a LinqDataSource

Recently, I was making a seemingly harmless LinqDataSource and I came across this error. I was using the simple (I thought):
Where="title.Contains(@title)"

This error kept popping up and confusing me... Contains sure does exist in String, so why the error?

Turns out that it is trying to run Contains on a NULL - and where does that NULL come from? A tricky little property in your ControlParameter that defaults to true, and you have to manually change it to false:
ConvertEmptyStringToNull="false"

And that should cause your Contains to work now, because every string Contains a String.Empty.