Re: Convert ListBox selectedvalue into INT - C# Discussion Boards

if I have event jump and I have blobs that link to it can I use the event to get links to the blobs how, and yes I think the event holds the refs some how. Suspicious | :suss:

See this code:
string msg = "My name is ABC, hello there";
MessageBox.Show(msg);

Now I would like to add a parammeter to msg so that I can change the name, for example
string msg = "My name is {0}, hello there";

I don't like the following way for some reasons:
string msg1 = "My name is ";
string msg2 = ", hello there";
string name = "ABC";
then
MessageBox.Show(msg1 + name + msg2);

But I don't know how to do it.

String name = "ABC";
String msg = String.Format("My name is {0}, hello there",name);
msgBox.Show(msg);

Anger is the most impotent of passions. It effects nothing it goes about, and hurts the one who is possessed by it more than the one against whom it is directed.
Carl Sandburg

Hi,

I am installing some softwares to Windows 2003. Those softwares, after being installed, will add some COM+ components to COM+ Application under Component Services. Now I just want to write a piece of code to read the names of COM+ components that have just been added.
Can u guys give me some hints?

Thanks

Hai,

Below is the code i saw @

http://support.microsoft.com/default.aspx?scid=kb;en-us;301240.

Pl go tho' the ex & ans my qns

every thing is fine but sql connection path iam having doubt. actually iam using sql server 2000. in pubs database i have run the below given code.

conn = new SqlConnection( "server=localhost;Integrated Security=SSPI;database=pubs" );

my qn is wht should my connection path should be. directly windows based login iam using for sql server.

Think u got my qns . pl ans

chand

Create an ASP.NET Application Using C# .NET
1. Open Visual Studio .NET.
2. Create a new ASP.NET Web application, and specify the name and location.
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Configure the Security Settings in the Web.config File
This section demonstrates how to add and modify the <authentication> and <authorization> configuration sections to configure the ASP.NET application to use forms-based authentication. 1. In Solution Explorer, open the Web.config file.
2. Change the authentication mode to Forms.
3. Insert the <forms> tag, and fill the appropriate attributes. (For more information about these attributes, refer to the MSDN documentation or the QuickStart documentation that is listed in the REFERENCES section.) Copy the following code, and then click Paste as HTML on the Edit menu to paste the code in the <authentication> section of the file:
<authentication mode="Forms">
<forms name=".ASPXFORMSDEMO" loginurl="logon.aspx"
="" protection="All" path="/" timeout="30">

4. Deny access to the anonymous user in the <authorization> section as follows:
<authorization>
<deny users="?">
<allow users="*">

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Create a Sample Database Table to Store Users Details
This section demonstrates how to create a sample database to store the user name, password, and role for the users. You need the role column if you want to store user roles in the database and implement role-based security. 1. On the Start menu, click Run, and then type notepad to open Notepad.
2. Highlight the following SQL script code, right-click the code, and then click Copy. In Notepad, click Paste on the Edit menu to paste the following code:
if exists (select * from sysobjects where id =
object_id(N'[dbo].[Users]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [dbo].[Users]
GO
CREATE TABLE [dbo].[Users] (
[uname] [varchar] (15) NOT NULL ,
[Pwd] [varchar] (25) NOT NULL ,
[userRole] [varchar] (25) NOT NULL ,
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[Users] WITH NOCHECK ADD
CONSTRAINT [PK_Users] PRIMARY KEY NONCLUSTERED
(
[uname]
) ON [PRIMARY]
GO

INSERT INTO Users values('user1','user1','Manager')
INSERT INTO Users values('user2','user2','Admin')
INSERT INTO Users values('user3','user3','User')
GO

3. Save the file as Users.sql.
4. On the Microsoft SQL Server computer, open Users.sql in Query Analyzer. From the list of databases, click pubs, and run the script. This creates a sample users table and populates the table in the Pubs database to be used with this sample application.
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Create a Logon.aspx Page
1. Add a new Web Form to the project named Logon.aspx.
2. Open the Logon.aspx page in the editor, and switch to HTML view.
3. Copy the following code, and use the Paste as HTML option on the Edit menu to insert the code between the tags:

Logon Page

Email:		<asp:requiredfieldvalidator controltovalidate="txtUserName" ="" display="Static" errormessage="*" runat="server" id="vUserName">
Password:		<asp:requiredfieldvalidator controltovalidate="txtUserPass" ="" display="Static" errormessage="*" runat="server" id="vUserPass">
Persistent Cookie:	<asp:checkbox id="chkPersistCookie" runat="server" autopostback="false">

<asp:label id="lblMsg" forecolor="red" font-name="Verdana" font-size="10" runat="server">

This Web Form is used to present a logon form to users so that they can provide their user name and password to log on to the application.
4. Switch to Design view, and save the page.
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Code the Event Handler So That It Validates the User Credentials
This section presents the code that is placed in the code-behind page (Logon.aspx.cs). 1. Double-click Logon to open the Logon.aspx.cs file.
2. Import the required namespaces in the code-behind file:
using System.Data.SqlClient;
using System.Web.Security;

3. Create a ValidateUser function to validate the user credentials by looking in the database. (Make sure that you change the Connection string to point to your database).
private bool ValidateUser( string userName, string passWord )
{
SqlConnection conn;
SqlCommand cmd;
string lookupPassword = null;

// Check for invalid userName.
// userName must not be null and must be between 1 and 15 characters.
if ( ( null == userName ) || ( 0 == userName.Length ) || ( userName.Length > 15 ) )
{
System.Diagnostics.Trace.WriteLine( "[ValidateUser] Input validation of userName failed." );
return false;
}

// Check for invalid passWord.
// passWord must not be null and must be between 1 and 25 characters.
if ( ( null == passWord ) || ( 0 == passWord.Length ) || ( passWord.Length > 25 ) )
{
System.Diagnostics.Trace.WriteLine( "[ValidateUser] Input validation of passWord failed." );
return false;
}

try
{
// Consult with your SQL Server administrator for an appropriate connection
// string to use to connect to your local SQL Server.
conn = new SqlConnection( "server=localhost;Integrated Security=SSPI;database=pubs" );
conn.Open();

// Create SqlCommand to select pwd field from users table given supplied userName.
cmd = new SqlCommand( "Select pwd from users where uname=@userName", conn );
cmd.Parameters.Add( "@userName", SqlDbType.VarChar, 25 );
cmd.Parameters["@userName"].Value = userName;

// Execute command and fetch pwd field into lookupPassword string.
lookupPassword = (string) cmd.ExecuteScalar();

// Cleanup command and connection objects.
cmd.Dispose();
conn.Dispose();
}
catch ( Exception ex )
{
// Add error handling here for debugging.
// This error message should not be sent back to the caller.
System.Diagnostics.Trace.WriteLine( "[ValidateUser] Exception " + ex.Message );
}

// If no password found, return false.
if ( null == lookupPassword )
{
// You could write failed login attempts here to event log for additional security.
return false;
}

// Compare lookupPassword and input passWord, using a case-sensitive comparison.
return ( 0 == string.Compare( lookupPassword, passWord, false ) );

}

4. You can use one of two methods to generate the forms authentication cookie and redirect the user to an appropriate page in the cmdLogin_ServerClick event. Sample code is provided for both scenarios. Use either of them according to your requirement. • Call the RedirectFromLoginPage method to automatically generate the forms authentication cookie and redirect the user to an appropriate page in the cmdLogin_ServerClick event:
private void cmdLogin_ServerClick(object sender, System.EventArgs e)
{
if (ValidateUser(txtUserName.Value,txtUserPass.Value) )
FormsAuthentication.RedirectFromLoginPage(txtUserName.Value,
chkPersistCookie.Checked);
else
Response.Redirect("logon.aspx", true);
}

• Generate the authentication ticket, encrypt it, create a cookie, add it to the response, and redirect the user. This gives you more control in how you create the cookie. You can also include custom data along with the FormsAuthenticationTicket in this case.
private void cmdLogin_ServerClick(object sender, System.EventArgs e)
{
if (ValidateUser(txtUserName.Value,txtUserPass.Value) )
{
FormsAuthenticationTicket tkt;
string cookiestr;
HttpCookie ck;
tkt = new FormsAuthenticationTicket(1, txtUserName.Value, DateTime.Now,
DateTime.Now.AddMinutes(30), chkPersistCookie.Checked, "your custom data");
cookiestr = FormsAuthentication.Encrypt(tkt);
ck = new HttpCookie(FormsAuthentication.FormsCookieName, cookiestr);
if (chkPersistCookie.Checked)
ck.Expires=tkt.Expiration;
ck.Path = FormsAuthentication.FormsCookiePath;
Response.Cookies.Add(ck);

string strRedirect;
strRedirect = Request["ReturnUrl"];
if (strRedirect==null)
strRedirect = "default.aspx";
Response.Redirect(strRedirect, true);
}
else
Response.Redirect("logon.aspx", true);
}

5. Make sure that the following code is added to the InitializeComponent method in the code that the Web Form Designer generates:
this.cmdLogin.ServerClick += new System.EventHandler(this.cmdLogin_ServerClick);

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Create a Default.aspx Page
This section creates a test page to which users are redirected after they authenticate. If users browse to this page without first logging on to the application, they are redirected to the logon page. 1. Rename the existing WebForm1.aspx page as Default.aspx, and open it in the editor.
2. Switch to HTML view, and copy the following code between the tags:

This button is used to log off the forms authentication session.
3. Switch to Design view, and save the page.
4. Import the required namespaces in the code-behind file:
using System.Web.Security;

5. Double-click SignOut to open the code-behind page (Default.aspx.cs), and copy the following code in the cmdSignOut_ServerClick event handler:
private void cmdSignOut_ServerClick(object sender, System.EventArgs e)
{
FormsAuthentication.SignOut();
Response.Redirect("logon.aspx", true);
}

6. Make sure that the following code is added to the InitializeComponent method in the code that the Web Form Designer generates:
this.cmdSignOut.ServerClick += new System.EventHandler(this.cmdSignOut_ServerClick);

7. Save and compile the project. You can now use the application.
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Additional Notes
• You may want to store passwords securely in a database. You can use the FormsAuthentication class utility function named HashPasswordForStoringInConfigFile to encrypt the passwords before you store them in the database or configuration file.
• You may want to store the SQL connection information in the configuration file (Web.config) so that you can easily modify it if necessary.
• You may consider adding code to prevent hackers who try to use different combinations of passwords from logging on. For example, you can include logic that accepts only two or three logon attempts. If the user cannot log on in a certain number of attempts, you may want to set a flag in the database to not allow that user to log on until that user re-enables his or her account by visiting a different page or by calling your support line. In addition, you should add appropriate error handling wherever necessary.
• Because the user is identified based on the authentication cookie, you may want to use Secure Sockets Layer (SSL) on this application so that no one can deceive the authentication cookie and any other valuable information that is being transmitted.
• Forms-based authentication requires that your client accept or enable cookies on their browser.
• The timeout parameter of the <authentication> configuration section controls the interval at which the authentication cookie is regenerated. You can choose a value that provides better performance and security.
• Certain intermediary proxies and caches on the Internet may cache Web server responses that contain Set-Cookie headers, which are then returned to a different user. Because forms-based authentication uses a cookie to authenticate users, this can cause users to accidentally (or intentionally) impersonate another user by receiving a cookie from an intermediary proxy or cache that was not originally intended for them. The following article explains how to combat

Hi!
I have a ListBox and I can get the selectedvalue. This selectedvalue is an int ID from an Access table. I have also checked the datatype by: textBox2.Text=ltbxLeft.SelectedValue.GetType().ToString(); It shows: System.Int32 .

My problem is that I cann't convert this ltbxLeft.SelectedValue into an integer. such as: int id=int.Parse(ltbxLeft.SelectedValue.ToString());

I got en error message saying: System.FormatException: Input string was not in a correct format.

Please help.

There is another property called SelectedIndex that does this for you. If you have object "o"...

"o.SelectedItem" and "o.Items[o.SelectedIndex]" both refer to the same object in the collection.

Thanks for your reply.

This is a Windows Forms application.

I use "ltbxLeft.DisplayMember" to display company name, use "ltbxLeft.ValueMember" to get the ID of the company:

ltbxLeft.DataSource = this.dataSet.Tables[tableName];
ltbxLeft.DisplayMember = columnName;
ltbxLeft.ValueMember = columnID;

By calling this method: "private void ltbxLeft_SelectedValueChanged(object sender, System.EventArgs e)", I can get:
ltbxLeft.SelectedIndex, ltbxLeft.SelectedValue, and ltbxLeft.SelectedItem

Everything works just fine, except that I cann't convert the ltbxLeft.SelectedValue, (which is an integer/the company ID in the table), into an integer, by whatever means (int.Parse; Convert.Int32,.....).

ltbxLeft.SelectedIndex gives me the number of the clicked listbox item (0,1,2...);
ltbxLeft.SelectedItem gives me the company name (by using dr = (DataRowView)(ltbxLeft.SelectedItem) to get it).

I can also get a string from ltbxLeft.SelectedValue.ToString() and display it in a textbox.

But I cann't convert this string into integer.

I have read Microsoft's example on http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemwindowsformslistcontrolclassselectedvaluechangedtopic.asp

which is about "ListControl.SelectedValueChanged Event". I have run the example, tried to modify the code and tried to convert the string in the example. I got the same problem!

Jeff Levinson wrote the following in DotNetMonster (http://www.dotnetmonster.com/Uwe/Forum.aspx/dotnet-general/762/ListBox-Problem).

I think he is right. But I donn't know how to use thte CType. I got a namespace problem with Ctype.

Jeff Levinson------------
The key thing to remember in .NET is that combo and list
boxes do not store simple values, they store types. So
what you've done in this situation is you've bound a
dataset or a datatable to the listbox. You've set it up
to display one value by setting the DisplayMember
property. At this point you can do two things:
1. Set the ValueMember property (and use the
Listbox.SelectedValue property to retrieve the
information which returns a discreet value) or
2. Perform a ctype on the selected item to convert it to
a datarow and then extract the value you want.

Option 2 is more flexible, but Option 1 is a faster
operation.

Iam doing this for a combo
int nExpMonthIndex =
Convert.ToInt32(cmbExpMonth_ACL.SelectedValue.ToString());

The same thing can be applied to list box.

Hope this helps.

saleem

Thanks for your help. But it doesn't work for me.

I have tried exactly the same: int id= Convert.ToInt32(ltbxLeft.SelectedValue.ToString()).

But I got en error:
System.FormatException: Input string was not in a correct format.

If I use textBox1.Text = ltbxLeft.SelectedValue.ToString(), then I can have a string value (for example 13).

But I cann't convert this string into en integer.

Is it possible to write a program in C# that will not compile for the .Net run time? I’m not sure if this question is clear, let me try again. C++, depending on the compiler lets you compile to many platforms is the same true for C# and if so can anyone recommend a compiler other than VS?

Thanks
Ron

Ronald Hahn, CNT - Computer Engineering Technologist

New Technologies Analyst

HahnTech Affiliated With Code Constructors
Edmonton, Alberta, Canada
Email: rhahn82@telus.net

No. All of the managed languages (C#, VB.NET, J#, ...) are compiled into Intermediate Language, or IL, not machine code! When launched, the application is compiled into native machine code by the CLR's JIT compiler the first time that it is needed. So, no, C# can't run without the .NET Framework.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Using NGen.exe utility from .NET Framework SDK you can compile whole assemble into into processor native language and save the result in a file. CLR detects already compiled code and runs the application without launching JIT-debugger.

adocoder.

That’s what I was afraid of. Thanks a lot for you quick responses Smile | :)

Time to dust off the ol' C++ books

Ronald Hahn, CNT - Computer Engineering Technologist

New Technologies Analyst

HahnTech Affiliated With Code Constructors
Edmonton, Alberta, Canada
Email: rhahn82@telus.net

There is an alternative compiler - Borland C#Builder.

Hi all!
I need to make a form with a DataGrid, that would represent a two-dimensional matrix. I woul look like this DataGrid[Account,Month] = Sum. I have a fixed collection of accounts. The user enters a period [StartMonth;FinishMonth] and the Grid calculates the sum of money, spent for each expense Account in each Month and represents it in a form of a matrix.
The problem is that we don't know the number of columns (months in the period) before we run the program. That's why we can't determine the structure of the cless that would represent a row for our Grid. The MAIN PROBLEM is: How can I create a Grid where the number of columns is calculated at runtime? What class should I use as a DataSource for my DataGrid? And what kind of element (class) should I use to supply data for this DataSource?

Thank you in advance for your help.

adocoder.

Hi,

I have used a colormatrix before to convert an image into black and white (code included), I now want to adapt this code so that i can convert the image to sepia, does anyone know the colour quantities for this?

ColorMatrix cm = new ColorMatrix(new float[][]{ new float[]{0.3f,0.3f,0.3f,0,0},
new float[]{0.59f,0.59f,0.59f,0,0},
new float[]{0.11f,0.11f,0.11f,0,0},
new float[]{0,0,0,1,0,0},
new float[]{0,0,0,0,1,0},
new float[]{0,0,0,0,0,1}});

Any help would be great,

Thanks

http://blogs.techrepublic.com.com/howdoi/?p=120[^]

it does not work for me though, it produces the same effect as grayscale. maybe i got something wrong there, goodluck

From the How do I... article's Listing B, the sepia matrix would be:

C#

ColorMatrix colorMatrix = new ColorMatrix(new float[][]
{
    new float[] {.393f, .349f, .272f, 0, 0},
    new float[] {.769f, .686f, .534f, 0, 0},
    new float[] {.189f, .168f, .131f, 0, 0},
    new float[] {0, 0, 0, 1, 0},
    new float[] {0, 0, 0, 0, 1}
});

Don Grout
Email: don@dgsoftware.ca
Web : http://www.dgsoftware.ca/

Hello all,

I decided to use BinaryFormatter to serialize the data of an application and I intended to create a small document easy to transport, etc. The problem is that the serialization takes a long time to do this task and the file size gets too much larger than I thought it to be.

Does anyone know how can I get through it? Is there some way to optimize the serialization task so that I can have smaller files in a shorter time??

Thanks,

Fernando Miranda
Programmer
Rio de Janeiro - Brazil.

Does the object to be serialized have references to other objects (reference types)? If so, all of those references will also be serialized. Likewise, events will also be serialized.

The most exciting phrase to hear in science, the one that heralds the most discoveries, is not 'Eureka!' ('I found it!') but 'That's funny...’

The objects to be serialized have references and events, and I know that BinaryFormatter takes the object in its argument list as the root of a graph linked by references to other objects and delegates signatures. So, to avoid this sort of problem, I cut off all references to objects and delegates that don´t need to be serialized. But I still have an undesired (and unreasonable) file size and serialization time.

A question: the BinaryFormatter takes in account file size optimization? Is there any other formatter that does it better? Any suggestion??

Another question: Does anyone know where can I find serialization documentation outside MSDN? (Sometimes I got a feeling MSDN documents say what they would like the classes to do, not what is done for real...)

Att,

Fernando Miranda
Software Developer
fmarcos.rj@ig.com.br
Rio de Janeiro - Brazil

I am using C# with SQL Server 2000 and Win 2K.I am having an extremely irritating problem.

I am making a query against the database using the dataset "fill()" command. The query takes about between 15 and 30 seconds to complete. Upon return, I get a dataset with a table collection added to the dataset but the collection is empty. If I copy the query and paste it into Query Analyzer, I get data. It takes about 15 to 30 seconds for it to run in QA, which tells me that it is executing both from QA and from the program. But, I still can't get a populated dataset. I have thrown exceptions handlers around the code and no exceptions are triggered by the fill command. I am setting the timeout to 600 which should be plenty long enough to prevent a timeout, but still no data.
Mad | :mad:

What could be causing this to happen?

a snippet of your code might help.

Anger is the most impotent of passions. It effects nothing it goes about, and hurts the one who is possessed by it more than the one against whom it is directed.
Carl Sandburg