Re: problem while retrving image from database. - C# Discussion Boards

Hello Christian,

The application works on few computers and does not work on the others.
I work on ASIA domain while the client for whom the application is written works in EUROPE domain. Even there, the application does not work on Laptop's.
I am not aware of what is amiss.
Can you tell me what are the features i need to look into?

Thanks.

Hello I'm working on a semi-script engine (using Reflection) and I have this class:

<code>
public enum LogicalOperator { EQL, NEQ, GTR, LSS, LEQ, GEQ };
public class Condition
{
public string instancename, fieldname;
public LogicalOperator logic;
public object value;
public Condition(string instancename, string fieldname, LogicalOperator logic, object value)
{
this.instancename = instancename;
this.fieldname = fieldname;
this.logic = logic;
this.value = value;
}
public Condition()
{
}
public bool Eval(object target)
{
object myValue = null;
try
{
myValue = target.GetType().GetField(this.fieldname).GetValue(target);
if (myValue == null)
{
myValue = target.GetType().GetProperty(this.fieldname).GetValue(target, null);
}
switch (this.logic)
{
case LogicalOperator.EQL: return myValue == this.value;
case LogicalOperator.NEQ: return myValue != this.value;
case LogicalOperator.GTR: return (float)myValue > (float)this.value;
case LogicalOperator.LSS: return (float)myValue < (float)this.value;
case LogicalOperator.LEQ: return (float)myValue <= (float)this.value;
case LogicalOperator.GEQ: return (float)myValue >= (float)this.value;
default: return false;
}
}
catch (NullReferenceException)
{
return false;
}
}
}
</code>

This works fine, but the problem is that I need some function like <i>GetObjectInstanceByName(this.instancename</i>), where instancename is a string and the return value is the instance as object.

I.e.: <i>Button myButton = GetObjectInstanceByName("Form1.button1") as Button;</i>

I've been surfering the net but I've don't found anything. How can I do this?

Thanks

You can call a constructor with reflection, I thought.

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

I don't want to create a new instance of a type, I want to reference an existing instance of any type, using its name as a string parameter.

Your best bet is to build a dictionary/hashtable mapping strings to objects, because you're not going to get that any other way.

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

Hi,
iam doing windows application c#

my database is "Firebird Database";

iam able to insert an picture into database,but iam unable to retrive the same..
my code is :
int id = int.Parse(textBox1.Text);
FbConnection cnn = new FbConnection("ServerType=1;User=SYSDBA;Password=masterkey;Database=E:/database/test.fdb");
cnn.Open();
string query = "select photo from cust1 where id=" + id;
FbDataAdapter adb = new FbDataAdapter(query, cnn);
DataSet ds = new DataSet();
adb.Fill(ds, "cust1");
DataRowCollection rdsrows = ds.Tables[0].Rows;

if (!rdsrows[0][0].Equals(DBNull.Value))
{
byte[] content = (byte[])rdsrows[0][0];
MemoryStream stream = new MemoryStream(content);
Bitmap img = new Bitmap(stream);-------------------"Error Here"
pictureBox1.Image = img;
}

it's giving error "parameter is not valid"
please inform where the problem is

murali krishna

modified on Monday, February 25, 2008 1:36 AM

Have you looked in the debugger to see what content looks like ? Compared it with the bytes of an image you're passing in ?

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

Hi,
Thanks for your reply.
while saving content with in bytes is showing Dimensions{77500} like this

but while retriving content with in bytes showing Dimensions{13} only..

murali krishna

Well, gee, that seems like it could be a problem....

Sounds like your code to store the image is broken. I assume there's not more than 13 bytes in your database.

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

Try using Image instead of Bitmap.
Are you sure that the photo field type is BLOB (binary)?

I have no idea of what happens here, but I have some experience with Firebird in C# (sourceforge.net/projects/pokelib) and I wrote some functions for image conversion:

<br />
public static byte[] FileToBytes(string filePath)<br />
        {<br />
            FileStream fs;<br />
            try<br />
            {<br />
                fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);<br />
            }<br />
            catch (IOException)<br />
            {<br />
                return null;<br />
            }<br />
<br />
            // Create a byte array of file stream length<br />
            byte[] fileData = new byte[fs.Length];<br />
<br />
            //Read block of bytes from stream into the byte array<br />
            fs.Read(fileData, 0, System.Convert.ToInt32(fs.Length));<br />
<br />
            //Close the File Stream<br />
            fs.Close();<br />
            return fileData;<br />
        }<br />
<br />
public static Image FileToImage(string imagePath)<br />
        {<br />
            FileStream fs;<br />
            try<br />
            {<br />
                fs = new FileStream(imagePath, FileMode.Open, FileAccess.Read);<br />
            }<br />
            catch (IOException)<br />
            {<br />
                return null;<br />
            }<br />
<br />
            // Create a byte array of file stream length<br />
            byte[] imageData = new byte[fs.Length];<br />
<br />
            //Read block of bytes from stream into the byte array<br />
            fs.Read(imageData, 0, System.Convert.ToInt32(fs.Length));<br />
<br />
            //Close the File Stream<br />
            fs.Close();<br />
            MemoryStream ms = new MemoryStream(imageData);<br />
            return Image.FromStream(ms);<br />
        }<br />
<br />
        public static byte[] ImageToBytes(Image imageIn)<br />
        {<br />
            MemoryStream ms = new MemoryStream();<br />
            imageIn.Save(ms, imageIn.RawFormat);<br />
            return ms.ToArray();<br />
        }<br />
<br />
        public static Image BytesToImage(byte[] byteArrayIn)<br />
        {<br />
            MemoryStream ms = new MemoryStream(byteArrayIn);<br />
            Image returnImage = Image.FromStream(ms);<br />
            return returnImage;<br />
        }

Try this: How To Read and Write BLOB Data by Using ADO.NET with Visual C# .NET[^]

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Hi all,
I am running SSIS package from C# that works fine if the stpes contains sql statements only,
but if some steps contain VB script or other language then it fails

can anybody tell me how to execute the SSIS package that contains combnation of steps and may be some steps contains VB script etc..

Thanks In advance....

vikas da

Hi,

I am having a problem that I have been trying to solve for the last 2 weeks. This might be seen in many travel sites like lastminute.com. The situation is simple. I need an indeterminate progress bar. I enter the search criteria/parameters (From/To Date & Destination) in page ‘A’. I click the search button now. I need to be transferred to Page ‘B’, which is empty but consists of a progress bar like image displaying any message and then I need to be transferred to page ‘C’ where the results will be displayed. I use the term “Indeterminate”, coz the progress bar is displayed based on the time taken (which can vary) to display the results and it not a fixed time interval(Usually with thread. sleep type) like u see in many sites. I am using VS 2005 + MS SQL 2005 + ASP.NET 2.0 + AJAX 1.0. Please help me out. Thank you

Regards,
balaji

The progress bar you're seeing is an animated gif. Add an animated gif to your page and show/hide it as you do your AJAX calls.

Please ask ASP.NET questions in the ASP.NET forum in future.

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

Hello friends,
I want to generate unique random numbers like if user want to generate random number between 100 to 500 then the number generated between them should be unique..
But there is a problem that number that i have generated are not unique my code is.

Random b = new Random();
string from = textBox3.Text;
string end = textBox4.Text;
int min= Convert.ToInt32(from);
int max = Convert.ToInt32(end);
for (int i = min; i <= max; i++)
{

listBox1.Items.Add(b.Next(min, max));
}

this code generate random number between min amd max but they are not unique.

The way to stop your numbers from repeating is to build a list of numbers ( so, from 100 to 500 ), then generate random numbers, the first would be between 0 and 399. Then you grab the number at that index in your list, and remove it. So, every time, the maximum value for your random number goes down by one ( use the Count property of the list for this ).

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

Sir thanks for suggestion.
But i am new in .NET so please can you give me code of this problem..

because i have tried what u write but i am unable to achieve it

Regards
Dikshant

It's incredibly straightforward, do you own any C# books ? You should buy one and work through it.

The steps are

List<int> list = new List<int>();

for(int 100;n<=500;++n)
{
list.Add(n);
}

Then when you want a number, generate a randon number between 0 and list.Count - 1. Grab that value and then remove it from the list.

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

Hi all,

I used the Timer class to make a tick event in specific interval, in my C# .Net service. My attempt as follows.

private System.Timers.Timer TimerTicker = null;
public RfService()
{
    InitializeComponent();

    const double INTERVAL = 10000;

    TimerTicker = new System.Timers.Timer( INTERVAL );
    TimerTicker.Elapsed += new ElapsedEventHandler( this.ServiceTimer_Tick );
}

Here, ServiceTimer_Tick() do my processing part.

My question is this. Immediately after starting my service start to count the tick on each 10 seconds and do the processing. That's fine, and work it well.

But, I want to hold the tick for 2 minutes immediately after starting the service and then do the 10 seconds interval process. That mean only the first time I want to hold the tick for 2 minutes.

I think it is clear for you. How can I do this. I'm really new for C#. Specially on threading, because I found that using threading I can do that.... Smile | :)

Thanks

I appreciate your help all the time...
Eranga Smile | :)

It's pretty straightforward. Set the interval to whatever you want it to be for the first tick, and in ServiceTimer_Tick, set the interval property of the timer to whatever you want it to be afer that.

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

If I get you correctly, you ask me to use two tick event. Yes I think that. But one of tick event execute only one time, stop it after 2 minute.

And also I do all those things in constructor method. Frown | :(

I appreciate your help all the time...
Eranga Smile | :)

No, not even remotely.

The timer has an interval property. Inside your tick event, set the Interval property to the value you want it to be after the first time it fires.

All I am suggesting is you do something like

Timer.Interval = 2000; // 2 seconds

inside the tick event.

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

Ok, I got the point and I'll try it now.

I appreciate your help all the time...
Eranga Smile | :)

Hi to ALL...

i have one doubt regarding to my project ...i have one compiled socket source code .In this source code are fully worked Windows XP...but in this code is not suitable for vista(not compiled)..
what is the problem for this ?
Whats the solution for that?
Is there any DLL corruption or not?If it is yes what kind of DLL add that problem ..?

....Please give your suggestion or any URL ...

*****THANKS N ADVANCE****
Mathen.K
(I WILL TRY MY LEVEL BEST )

What's the actual issue ? Sounds to me like Vista is blocking your sockets. If it won't build under vista, then post your errors.

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )