Bilal Haidar [MVP] : ASP.NET 2.0

Maintain Position In ASP.NET 2.0

simple — Tue, 06 Dec 2005 20:04:00 GMT

A new trick in ASP.NET 2.0 to maintain position upon postback is as follows:

<%@ Page Language="VB" MaintainScrollPositionOnPostBack="true" %>

<%@ Page Language="C#" MaintainScrollPositionOnPostBack="true" %>

Regards

An Extended Look at the Profile Object - Part 3

simple — Mon, 05 Dec 2005 13:39:00 GMT

Dear all:

I would like to announce my third article in the series of ASP.NET 2.0, the Profile object.

You are all welcome to check my article at the following URL:

An Extended Look at the Profile Object - Part 3

Regards

CustomValidator in ASP.NET 2.0

simple — Fri, 25 Nov 2005 13:51:00 GMT

Check out this Tip:

The ValidateEmptyText property, new in ASP.NET 2.0, fixes an issue with CustomValidator.

In ASP.NET 1.0 custom validation would not fire if ValidationText was empty.

You can set this property to true to cause custom validation to occur for empty input values.

Regards

Using SQL Transactions Properly

simple — Mon, 21 Nov 2005 19:29:00 GMT

Today, I was creating a small tiny script to generate a set of acocunts to be placed in my Database at work. I thought that such a small script doesn't require creating Stored Procedures. So I thought of using simple scripts to execute. However, I had a requirement which was that, if one transaction failed, I must stop the execution of all other scripts executing. I remember I can use SqlTransactions inside my C# code, and not inside TSQL Stored Procedures. Make sure always, when you have a set of SQL queries to execute to use SqlTransaction. The code below works for both ASP.NET 1.x/2.0.

using ( SqlConnection DbConnection = 
                new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString))
            {
                using (SqlCommand DbCommand = DbConnection.CreateCommand())
                {
                    SqlTransaction DbTransaction = null;

                    try
                    {
                        //Open connection required by BeginTransaction
                        DbConnection.Open();

                         // Begin the transaction
                        DbTransaction = DbConnection.BeginTransaction();

                         // Assign Transaction to Command
                        DbCommand.Transaction = DbTransaction;
 
                        // Execute Create User Command
                        DbCommand.CommandText = "INSERT INTO TableName(Name) VALUES ('Bilal Haidar')";
                        DbCommand.ExecuteNonQuery();

                         // Execute Get newly inserted User ID
                        DbCommand.CommandText = "SELECT MAX(UserID) FROM TableName"; 
                        int UserID = Convert.ToInt32(DbCommand.ExecuteScalar().ToString());

                         // If you reached this stage, commit transaction
                         DbTransaction.Commit();
                    }
                    catch
                    {
                        DbTransaction.Rollback();
                    }
              }

 }

Regards

VS.NET 2005 is Final

simple — Mon, 31 Oct 2005 19:27:00 GMT

Dear ASP.NET developers:

The VS.NET 2005 (Standard + Professional) is now available for all those who have MSDN Subscription. Go to http://msdn.microsoft.com/ and get your copy.

Enjoy Dot Netting !!

Regards

An Extended Look at the Profile Object - Part 2

simple — Tue, 25 Oct 2005 13:38:00 GMT

I would like to announce my second article in the series of articles on the Profile object, a new feature in ASP.NET 2.0

You may visit the article @ An Extended Look at the Profile Object - Part 2

Hope you are enjoying my articles.

Happy Dot Netting !!

Regards

Object Reference not set to an instance of an object in VS.NET 2005

simple — Thu, 13 Oct 2005 17:18:00 GMT

I faced a weird problem today while trying to add a new ASPX page into my working solution in Visual Studio.NET 2005. The problem is that I am unable to add a new ASPX page with code behind. I used to get the following error:

Object Reference Not set to an instance of the object or something like that

The solution was as follows:

1- Go to the following registry node: [HKEY_CURRENT_USER\Software\Classes]

2- Double-Click the key with type REG_SZ

3- Empty the “Vlaue Data” field, to make it with no data, press on

The problem is now solved.

Regards

An Extended Look at the Profile Object in ASP.NET 2.0

simple — Fri, 07 Oct 2005 14:01:00 GMT

I would like to announce my third article on the http://www.aspalliance.com:

An Extended Look at the Profile Object - Part 1

Hope you will benefit from it to the max.

Regards

Take your ASP.NET 2.0 Website Offline

simple — Fri, 07 Oct 2005 13:49:00 GMT

A very nice technique by the ASP.NET 2.0 Team,

You can now take your application offline by just placing a file called App_Offline.htm into the root folder of your application online.

What this file does is that, all requests to your application will be redirected to this page. You can place a message to your visitors saying that your application is under construction or your application is being maintained.

It is very usefull speially when you are doing some updates or maintenance to your application.

Happy DotNetting !!

Regards

Dynamic Loading of UserControl in ASP.NET 2.0 Beta 2

simple — Mon, 12 Sep 2005 20:00:00 GMT

I was trying to dynamically load a user control in an ASP.NET 2.0 project.

The problem was, the code-file could not be seen in my ASPX page.

To make this work, I did the following steps:

1- I put my usercontrol in a new normal folder called: App_UserControls,

2- Add this to the top of the ASPX page:

<%@ Register TagPrefix="uc1" TagName="TestControl" Src="App_UserControls/test.ascx" %>

<%@ Register TagPrefix="uc1" TagName="TestUC" Src="App_UserControls/test.ascx" %>

Then in my code-beside:

Control uc = this.LoadControl("~/App_UserControls/test.ascx");
((test)uc).Name = "Bilal Haidar";
phControls.Controls.Add(uc);

Now things are ok, but ...

The main problem is, why do we need to Register the user control in a time we are dyanamically laoding the user control?

Regards

FindPageControl :: Get Control inside a content page

simple — Fri, 02 Sep 2005 20:18:00 GMT

In my previous post, I talked a problem in ASP.NET 2.0 using Master Pages.

I recommend using the following:

In the BaseClass of your aspx pages in ASP.NET, add the following:

protected Control FindPageControl(string ControlName, string ContentHolderName)
{
       // Get the ContentPlaceHolder Control
      ContentPlaceHolder _CPH = 
                 (ContentPlaceHolder)this.Page.Controls[0].FindControl(ContentHolderName);
 
     // Get the required control inside ContentPlaceHolder control
     Control _ctrl = _CPH.FindControl(ControlName);

     return _ctrl;
}

In your aspx page, you can find the control as follows:

((CheckBoxList)this.FindPageControl("chkDays","ContentPlaceHolder1")).Items.Count

Hope that helps,

Regadrs

FindControl while using Master Pages

simple — Fri, 02 Sep 2005 15:37:00 GMT

There is something missing in ASP.NET 2.0 Master Pages Beta 2 in the way we access controls on the content page.

For example, I use the following lines of code to get a reference to the CheckBoxList (CheckDays) on a page placed inside the ContentPlaceHolder:

string ControlName = "ctl00$ContentPlaceHolder1$CheckDays";
CheckBoxList _chkList = (CheckBoxList)Page.FindControl(ControlName);

Shouldn't the ASP.NET 2.0 team find a solution in something like:

CheckBoxList _ckhList = this.FindControl("CheckDays") // this refers to ContentPalceHolder
 
 
Thank you,

Inside ASP.NET 2.0 Master Pages

simple — Thu, 01 Sep 2005 23:33:00 GMT

A great article on ASP.NET 2.0 Master Pages:

Inside ASP.NET 2.0 Master Pages

Regards

DateTime Formatting in ASP.NET 2.0

simple — Wed, 10 Aug 2005 14:26:00 GMT

This is a nice summarized sample code on how to format DateTime instances:

// This code example demonstrates the String.Format() method.
// Formatting for this example uses the "en-US" culture.

using System;
class Sample 
{
    enum Color {Yellow = 1, Blue, Green};
    static DateTime thisDate = DateTime.Now;

    public static void Main() 
    {
// Store the output of the String.Format method in a string.
    string s = "";

    Console.Clear();

// Format a negative integer or floating-point number in various ways.
    Console.WriteLine("Standard Numeric Format Specifiers");
    s = String.Format(
        "(C) Currency: . . . . . . . . {0:C}\n" +
        "(D) Decimal:. . . . . . . . . {0:D}\n" +
        "(E) Scientific: . . . . . . . {1:E}\n" +
        "(F) Fixed point:. . . . . . . {1:F}\n" +
        "(G) General:. . . . . . . . . {0:G}\n" +
        "    (default):. . . . . . . . {0} (default = 'G')\n" +
        "(N) Number: . . . . . . . . . {0:N}\n" +
        "(P) Percent:. . . . . . . . . {1:P}\n" +
        "(R) Round-trip: . . . . . . . {1:R}\n" +
        "(X) Hexadecimal:. . . . . . . {0:X}\n",
        -123, -123.45f); 
    Console.WriteLine(s);

// Format the current date in various ways.
    Console.WriteLine("Standard DateTime Format Specifiers");
    s = String.Format(
        "(d) Short date: . . . . . . . {0:d}\n" +
        "(D) Long date:. . . . . . . . {0:D}\n" +
        "(t) Short time: . . . . . . . {0:t}\n" +
        "(T) Long time:. . . . . . . . {0:T}\n" +
        "(f) Full date/short time: . . {0:f}\n" +
        "(F) Full date/long time:. . . {0:F}\n" +
        "(g) General date/short time:. {0:g}\n" +
        "(G) General date/long time: . {0:G}\n" +
        "    (default):. . . . . . . . {0} (default = 'G')\n" +
        "(M) Month:. . . . . . . . . . {0:M}\n" +
        "(R) RFC1123:. . . . . . . . . {0:R}\n" +
        "(s) Sortable: . . . . . . . . {0:s}\n" +
        "(u) Universal sortable: . . . {0:u} (invariant)\n" +
        "(U) Universal sortable: . . . {0:U}\n" +
        "(Y) Year: . . . . . . . . . . {0:Y}\n", 
        thisDate);
    Console.WriteLine(s);

// Format a Color enumeration value in various ways.
    Console.WriteLine("Standard Enumeration Format Specifiers");
    s = String.Format(
        "(G) General:. . . . . . . . . {0:G}\n" +
        "    (default):. . . . . . . . {0} (default = 'G')\n" +
        "(F) Flags:. . . . . . . . . . {0:F} (flags or integer)\n" +
        "(D) Decimal number: . . . . . {0:D}\n" +
        "(X) Hexadecimal:. . . . . . . {0:X}\n", 
        Color.Green);       
    Console.WriteLine(s);
    }
}
/*
This code example produces the following results:

Standard Numeric Format Specifiers
(C) Currency: . . . . . . . . ($123.00)
(D) Decimal:. . . . . . . . . -123
(E) Scientific: . . . . . . . -1.234500E+002
(F) Fixed point:. . . . . . . -123.45
(G) General:. . . . . . . . . -123
    (default):. . . . . . . . -123 (default = 'G')
(N) Number: . . . . . . . . . -123.00
(P) Percent:. . . . . . . . . -12,345.00 %
(R) Round-trip: . . . . . . . -123.45
(X) Hexadecimal:. . . . . . . FFFFFF85

Standard DateTime Format Specifiers
(d) Short date: . . . . . . . 6/26/2004
(D) Long date:. . . . . . . . Saturday, June 26, 2004
(t) Short time: . . . . . . . 8:11 PM
(T) Long time:. . . . . . . . 8:11:04 PM
(f) Full date/short time: . . Saturday, June 26, 2004 8:11 PM
(F) Full date/long time:. . . Saturday, June 26, 2004 8:11:04 PM
(g) General date/short time:. 6/26/2004 8:11 PM
(G) General date/long time: . 6/26/2004 8:11:04 PM
    (default):. . . . . . . . 6/26/2004 8:11:04 PM (default = 'G')
(M) Month:. . . . . . . . . . June 26
(R) RFC1123:. . . . . . . . . Sat, 26 Jun 2004 20:11:04 GMT
(s) Sortable: . . . . . . . . 2004-06-26T20:11:04
(u) Universal sortable: . . . 2004-06-26 20:11:04Z (invariant)
(U) Universal sortable: . . . Sunday, June 27, 2004 3:11:04 AM
(Y) Year: . . . . . . . . . . June, 2004

Standard Enumeration Format Specifiers
(G) General:. . . . . . . . . Green
    (default):. . . . . . . . Green (default = 'G')
(F) Flags:. . . . . . . . . . Green (flags or integer)
(D) Decimal number: . . . . . 3
(X) Hexadecimal:. . . . . . . 00000003

*/

This samlpe code is taken from:

http://msdn2.microsoft.com/library/system.string.format.aspx

Regards

SuperDropDownList 1.0

simple — Mon, 08 Aug 2005 15:20:00 GMT

Hello:
I have uploaded a new control on my personal website, under the title SuperDropDownList.
What this control does is the following:

1- Insert a default ListItem at the top of the data bounded DropDownList
2- Adds a RequiredFieldValidator to check whether the user has chosen the default ListItem or not.

This control does offer some properties to access the needed properties of the DropDownList.

Hope you will like it.

Check my website. Then go to the ASP.NET Components' Page.

Regards

Modal Dialog Window Caching Problem

simple — Sun, 07 Aug 2005 05:34:00 GMT

Hello:

Suppose you open a Modal Dialog window inside your ASP.NET page. In that dialog window, you have a GridView, DataGrid, or whatever control. Do some changes on that control, you will see that the data has changed right?

Ok, then close the dialog window, then open it again from the ASP.NET Page, you will see the old data and not the data you changed last time, right?

Ok, this is because the data has been cached by the Modal Dialog. It seems that this is how Modal Dialog Windows are built to cache.

To overcome this, you would need to add the following in the top of the ASP.NET page that is being opened with the Modal Dialog:

<%@ OutputCache Location="None" VaryByParam="None" %>

Hope that helps,

Regards

CheckBoxField in GridView

simple — Sun, 07 Aug 2005 05:17:00 GMT

In the new data control, GridView, you have a new column called CheckBoxField, this column, accepts a boolean value and display a CheckBox either selected or not and disabled.

What if you want to retreive the value from that column, to see if the CheckBox is selected or not?

CheckBox _checkBoxInGridRow = ((CheckBox)selectedRow.Cells[6].Controls[0]).Checked

Hope that helps,

Note: This code follows from this post: http://msmvps.com/simpleman/archive/2005/08/06/61782.aspx

Regards

DropDownList Tip

simple — Sat, 06 Aug 2005 21:35:00 GMT

Hi:

I was binding the DropDownList on an ASPX page in the Page_Load as follows:

this.TypesDDL.DataSourceID = this.TypesDDL.DataSourceID;

Then, after all I was adding the following:

this.TypesDDL.Items.Insert(0,new ListItem(”text”, “value”));

That item was inserted inside ANY POSITION in the TypesDDL.

Only after 1 hour of trying to find out what is going wrong, I noticed this Property of the DropDownList:

ListControl.AppendDataBoundItems Property

By definition, Append Data Bind Items to Statically Declared List Items

So once you set it to True, then you can add any item to the DropDownList or any control that inherits from ListControl, since that property belong to the ListControl.

Note to Server Controls' Builders: Make sure to set this property to true if you are using any ListControl inside your custom/composite controls.

Hope that tip helps,

Regards

Access Selected GridViewRow in GridView

simple — Sat, 06 Aug 2005 18:05:00 GMT

Hello:

I was working last night around 3:00 AM, and I found out that in my GridView Column's list, I have added a TemplateField of type LinkButton with CommandName=”EditRec”, in such a way, when the Edit link button is clicked, I want to access the selected GridViewRow, then populate a web form on the same page, and without having to show the “Update” and “Cancel” buttons on the GridView.

I did that, but the problem was now how to access the GridViewRow in the RowCommand method?

I used the “SelectedRow” property but I kept having “Object Reference not ....” I didn't know in fact.

I tried to use GridView1.Rows[e.CommandArgument], but the DataKey I set for the GridView was of type String, so cannot use that either.

I finally was able to use the following and it works fine for me:

if (e.CommandName.Equals("EditRec"))
  {
            string MediaIndex = e.CommandArgument.ToString();

            // Get the last name of the selected author from the appropriate
            // cell in the GridView control.
            GridViewRow selectedRow = (GridViewRow)(((Control)e.CommandSource).NamingContainer);

            string _mediaType   = selectedRow.Cells[0].Text;
            string _CheckOut    = selectedRow.Cells[1].Text;
}

The way the code works if as follows:

e.CommandSource -> LinkButton
((Control)e.CommandSource).NamingContainer -> GridViewRow

Then, simply use the Cells property inside the GridViewRow to access all cells.

Hope that Helps,

Regards

Insert a New Record Using GridView

simple — Mon, 01 Aug 2005 20:22:00 GMT

Here is a nice link to insert a new record into the database:

http://fredrik.nsquared2.com/viewpost.aspx?PostID=155

Regards