Re: Save and Retrieve Image - C# Discussion Boards

nirmalgopalakrishnan29-Dec-12 6:07

29-Dec-12 6:07

byte[] bytesofphotosretrive;
bytesofphotosretrive = (byte[])r["photo"];
MemoryStream mst = new MemoryStream(bytesofphotosretrive);
{
frm1.pictureBox5.Image = Image.FromStream(mst);
}

the error points to this parameter : frm1.pictureBox5.Image = Image.FromStream(mst);

Re: Save and Retrieve Image

Richard MacCutchan29-Dec-12 6:17

Richard MacCutchan

29-Dec-12 6:17

Well it should not be too difficult to guess which parameter is in error. Use your debugger to step through the code and see exactly what is happening.

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Re: Save and Retrieve Image

nirmalgopalakrishnan29-Dec-12 19:14

nirmalgopalakrishnan

29-Dec-12 19:14

It's pointing to the error in line 164, which is as below:

frm1.pictureBox5.Image = Image.FromStream(mst);

The exception message is: "System.Argument.Exception: Parameter is not valid. at System.Drawing.Image.FromStream(Stream stream, Boolean useEmbeddedColorManagement, Boolean validateImageData) at System.Drawing.Image.FromStream(Stream stream)at btnResearch_Click(Object sender, EventArgs e) in D:\Mat\frmRecSearch.cs: line 164.

Re: Save and Retrieve Image

Richard MacCutchan29-Dec-12 21:22

Richard MacCutchan

29-Dec-12 21:22

Well we already know that. Have you used the debugger to try and determine why the parameter is invalid?

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Re: Save and Retrieve Image

nirmalgopalakrishnan30-Dec-12 19:57

nirmalgopalakrishnan

30-Dec-12 19:57

Could you please email me. nirmalkumarg3@gmail.com

Re: Save and Retrieve Image

Richard MacCutchan30-Dec-12 22:19

Richard MacCutchan

30-Dec-12 22:19

Sorry no, if you have issues to discuss around this problem then post them in this forum; that is why we use it.

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Re: Save and Retrieve Image

nirmalgopalakrishnan31-Dec-12 17:28

nirmalgopalakrishnan

31-Dec-12 17:28

Cool, no issues. It points to a null parameter in the debugger. But the same code, when executed with just an image add and retrieve (a new c# project), the application works really well. I am unable to determine what is the problem here Frown | :(

Re: Save and Retrieve Image

Richard MacCutchan31-Dec-12 22:50

Richard MacCutchan

31-Dec-12 22:50

nirmalgopalakrishnan wrote:
I am unable to determine what is the problem here

From a previous post you have the following code:

byte[] bytesofphotosretrive;
bytesofphotosretrive = (byte[])r["photo"];
MemoryStream mst = new MemoryStream(bytesofphotosretrive);
{
    frm1.pictureBox5.Image = Image.FromStream(mst);
}

So you need to find out why mst is null at this point. Your code is assuming that you always get a valid byte array from r (whatever that is), and hence a valid stream. However, if either of these commands do not return the expected result you are going to have a problem which you are not catering for. You should never assume that method calls like this will always succeed; add some error checks so you can diagnose it properly when it fails.

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Re: Save and Retrieve Image

Abhinav S28-Dec-12 23:38

Abhinav S

28-Dec-12 23:38

Try this link out -http://guruparan.blog.com/2011/06/15/saving-and-retriving-images-from-mysql-databases-using-c-part2/[^].
An image is opened and then saved to the database.

In particular, note how longblob has been used to save the image in the database.

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Re: Save and Retrieve Image

nirmalgopalakrishnan29-Dec-12 5:16

nirmalgopalakrishnan

29-Dec-12 5:16

Thank you for your response. The link which you provided was really helpful. But i am not sure how to include the same in my application, since i am saving data from 15 text boxes.

I am confused as to where to include the image details.

Regards,
Nirmal

Dynamic text box array and focus event

Everetts28-Dec-12 8:41

Everetts

28-Dec-12 8:41

I have a form that has an array of text boxes dynamically added to a splitcontainer on a form. I use the same array to add text boxes to the form twice (different data for different table). I would like to use an event handler, preferably once, to change background color to yellow when textbox[i] receives focus, and back to white when it loses focus. I am currently going around in circles. Can anyone help me? Thanks for your input
Everett

Re: Dynamic text box array and focus event

Eddy Vluggen28-Dec-12 10:25

Eddy Vluggen

28-Dec-12 10:25

Add in a lambda, at the point where you create the textboxes. Like the example below;

public Form1()
{
    InitializeComponent();

    var tb = new TextBox();
    tb.GotFocus += delegate (object s, EventArgs a)
    {
        (s as TextBox).BackColor = Color.Red;
    };
    tb.LostFocus += delegate(object s, EventArgs a)
    {
        (s as TextBox).BackColor = Color.Green;
    };
    Controls.Add(tb);
}

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Re: Dynamic text box array and focus event

bambuz28-Dec-12 14:33

bambuz

28-Dec-12 14:33

hi, your idea is right, but the textbox has't the event GotFocus & LostFocus, instead of, has the event Enter & Leave.
Wink | ;)

Re: Dynamic text box array and focus event

Everetts28-Dec-12 16:41

Everetts

28-Dec-12 16:41

Works beeeautiful. Thank you so much Eddy
Everett

Connection String in Properties.Settings

TheJudeDude28-Dec-12 7:47

TheJudeDude

28-Dec-12 7:47

I am rewriting a desktop application in VS2010 that was written in .Net 1.1. While doing so, I decided to add a couple of features to the app. One is a data source for a drop down list. I am using a local database file (.sdf) for the data.
I noticed in the <namespace>.Properties.Settings file that the connection string is a hard link to where I entered the file location (which is C:\Users\<username>\Documents\db\<filename>). I need this to be more dynamic, due to the fact this app will be on many different computers.
I tried editing to :

"Data Source = " + System.Environment.GetFolderPath(System.Environment.SpecialFolder.MyDocuments) + @"\dbs\latefee.sdf")]

But I receive the following error at compile time:

Error	1	An attribute argument must be a constant expression, typeof expression or array creation expression of an attribute parameter type	C:\Users\brian\AppData\Local\Temporary Projects\latefeedisc\Properties\Settings.Designer.cs	29	68	latefeedisc

How do I correct this?

Thank you in advance.

Jude

Re: Connection String in Properties.Settings

SledgeHammer0128-Dec-12 8:27

SledgeHammer01

28-Dec-12 8:27

Didn't you read the warning at the top?

//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated by a tool.
// Runtime Version:4.0.30319.544
//
// Changes to this file may cause incorrect behavior and will be lost if
// the code is regenerated.
//
//------------------------------------------------------------------------------

?? Smile | :)

You aren't supposed to modify that file. You should set the property in the constructor of your window.

Re: Connection String in Properties.Settings

Eddy Vluggen28-Dec-12 8:30

Eddy Vluggen

28-Dec-12 8:30

TheJudeDude wrote:
I need this to be more dynamic

More dynamic than a settings-file? Smile | :)

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Re: Connection String in Properties.Settings

TheJudeDude28-Dec-12 8:49

TheJudeDude

28-Dec-12 8:49

I apologize for my ignorance.

Jude

Re: Connection String in Properties.Settings

Eddy Vluggen28-Dec-12 9:01

Eddy Vluggen

28-Dec-12 9:01

Don't. It wasn't "ignorant", just overlooked some semantics that "could" give a hint.

It's a real settings-file; now, if only the database-name (or path) is going to differ, it'd might be neat to use a connection-string with a literal set of characters in the place where the databasename should be, and to Replace the literal with the actual path just before using the string.

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Re: Connection String in Properties.Settings

PIEBALDconsult28-Dec-12 14:04

PIEBALDconsult

28-Dec-12 14:04

Oh, get off the Replace kick! Big Grin | :-D

Possibly use an environment variable and let the system do the replace.

But I suspect that the poster doesn't actually want to use the settings file at all. I'd write my own config file. :shrug:

Re: Connection String in Properties.Settings

SledgeHammer0129-Dec-12 7:18

SledgeHammer01

29-Dec-12 7:18

So, you want the system to do a simple literal replace for you, but you want to roll your own config file implementation? Clever D'Oh! | :doh:

. Are you also going to write all the cool stuff that you get for free with config files such as encryption, versioning, editing through a simple GUI in VS, backwards compatibility, etc?

Re: Connection String in Properties.Settings

PIEBALDconsult29-Dec-12 7:23

PIEBALDconsult

29-Dec-12 7:23

Yes.

Re: Connection String in Properties.Settings

SledgeHammer0129-Dec-12 7:29

SledgeHammer01

29-Dec-12 7:29

Why?

Re: Connection String in Properties.Settings

PIEBALDconsult29-Dec-12 7:43