Re: Creating a file and saving it to C - C# Discussion Boards

plz help!!error use of unassigned local variable

crisjala6-Apr-10 17:24

6-Apr-10 17:24

hi i just want to display all empty fieldnames that are not filled up by the user
but my code has this errorer ' use of unassigned local variable 'messEmptyField' ; how can i fix this

<br />
private void btnSave_Click(object sender, EventArgs e)<br />
        {<br />
          string[] FieldName = { "Lastname", "Firstname", "Address", "Model", "Trouble Reported" };<br />
          string messEmptyField;<br />
          int i = 0;<br />
<br />
            foreach (Control ctrl in groupBox1.Controls)<br />
            {<br />
                TextBox txt = ctrl as TextBox;<br />
<br />
                if (txt.Text == string.Empty)<br />
                {<br />
                    messEmptyField += FieldName[i]; //error use of unassigned local variable 'messEmptyField'<br />
                }<br />
                i++;<br />
            }<br />
<br />
            MessageBox.Show(messEmptyField + "please filled up all");<br />
            dtDateLog.Focus();<br />
            return;<br />
        }<br />
<br />
<br />
<br />
<br />

Re: plz help!!error use of unassigned local variable

Matt U.6-Apr-10 17:59

Matt U.

6-Apr-10 17:59

This line:

string messEmptyField;

should probably be:

string messEmptyField = string.Empty;

Re: plz help!!error use of unassigned local variable

uraghu6-Apr-10 18:22

uraghu

6-Apr-10 18:22

hi
try this
string messEmptyField="";

Re: plz help!!error use of unassigned local variable

Arun Jacob6-Apr-10 19:00

Arun Jacob

6-Apr-10 19:00

uraghu wrote:
string messEmptyField="";

Using string.Empty is the good practice.

Arun Jacob
http://codepronet.blogspot.com/

Re: plz help!!error use of unassigned local variable

Morgs Morgan6-Apr-10 20:58

Morgs Morgan

6-Apr-10 20:58

You can try the following:

string messEmptyField = ""; //declares an empty string

--the choice is all yours!-- $Shucks | :-\$

Re: plz help!!error use of unassigned local variable

OriginalGriff6-Apr-10 22:29

OriginalGriff

6-Apr-10 22:29

You can use String.Empty as the others say, or better still use StringBuilder:

private void btnSave_Click(object sender, EventArgs e)
   {
   string[] FieldName = { "Lastname", "Firstname", "Address", "Model", "Trouble Reported" };
   StringBuilder messEmptyField = new StringBuilder();
   int i = 0;

   foreach (Control ctrl in groupBox1.Controls)
      {
      TextBox txt = ctrl as TextBox;

      if (txt.Text == string.Empty)
         {
         messEmptyField.Append(FieldName[i]);
         }
      i++;
      }

   MessageBox.Show(messEmptyField.ToString() + "please filled up all");
   dtDateLog.Focus();
   return;
   }

You should never use standby on an elephant. It always crashes when you lift the ears. - Mark Wallace

C/C++ (I dont see a huge difference between them, and the 'benefits' of C++ are questionable, who needs inheritance when you have copy and paste) - fat_boy

Creating a file and saving it to C

Darrall6-Apr-10 14:09

Darrall

6-Apr-10 14:09

I am trying to create a simple text file and save it to C as:

File.Create(C:/Points.txt)

I am getting this error:

System.UnauthorizedAccessException was unhandled
Message="Access to the path 'C:\\Points.txt' is denied."
Source="mscorlib"
StackTrace:
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy)
at System.IO.FileStream..ctor(String path, FileMode mode, etc.

Can anyone tell me why? Its my computer and I am the sole user and administrator.

Thanks

Re: Creating a file and saving it to C

Super Lloyd6-Apr-10 14:32

Super Lloyd

6-Apr-10 14:32

Interesting, I tried and got the same error.
Then I tried with Notepad and I got the same error as well.

Seems to be one of those path were you need to be really the administrator (as in, if you said yes to an UAC prompt)

A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
_________________________________________________________
My programs never have bugs, they just develop random features.

Re: Creating a file and saving it to C

harold aptroot6-Apr-10 15:03

harold aptroot

6-Apr-10 15:03

I had absolutely no trouble doing this on XP, not even a warning. So I guess you're not using XP

Re: Creating a file and saving it to C

Darrall6-Apr-10 15:47

Darrall

6-Apr-10 15:47

No...Windows7

Re: Creating a file and saving it to C

Dan Mos6-Apr-10 16:49

Dan Mos

6-Apr-10 16:49

Hy,

3 options:

0) Disable the UAC or play with it until W7 will let you copy on root(c:\)
without the UAC prompt.

1) Implement a UAC like button or something for this purpose
Here's an example on how to bypass the UAC

2) Use the application folder

I highly recommed nr 2)

modified on Tuesday, April 6, 2010 10:56 PM

Re: Creating a file and saving it to C

Darrall7-Apr-10 4:47

Darrall

7-Apr-10 4:47

Thanks

Re: Creating a file and saving it to C

PIEBALDconsult6-Apr-10 15:24

PIEBALDconsult

6-Apr-10 15:24

Vista doesn't allow writing to the root directory; get a better operating system (XP).

Better yet, store application data in the application data directory.

Re: Creating a file and saving it to C

Darrall6-Apr-10 16:01

Darrall

6-Apr-10 16:01

Trouble with storing in the application directory is then you have to have the user browse to where he stored the application so you can pick up the path. Better than random locations on C I suppose.

Re: Creating a file and saving it to C

PIEBALDconsult6-Apr-10 16:13

PIEBALDconsult

6-Apr-10 16:13

The application data directory.

How to call a COM function with arguments using IDispatch in C#

JF Pomerleau6-Apr-10 11:27

JF Pomerleau

6-Apr-10 11:27

Hello everyone,

I need to call a function that needs arguments from a COM object using the IDispatch interface. I have been able to call functions that does not need parameters and to get values from properties of the COM object using the Invoke function of the IDispatch interface. However, I am unable to call a function with parameter using the Invoke function of IDispatch. I believe it is because I don't set in the proper way the value "rgvarg" of the DISPPARAMS structure that must be passed to the invoke function to represent the arguments that must be passed to the object function. DISPPARAMS.rgvarg is expecting a IntPtr that represent an array of objects.

Does anyone have done this?

Here is a sample code of my program.

Type tSWApp = Type.GetTypeFromProgID("SldWorks.Application");
object swApp = Activator.CreateInstance(tSWApp);
IDispatch idisp = (IDispatch)swApp;

// Getting the visible property (this part works)
Guid guid = new Guid();
int[] nIds = new int[] { 0 };
nRetVal = idisp.GetIDsOfNames(ref guid, new string[] { "Visible" }, 1, 0, nIds);

DISPPARAMS dispParams = new DISPPARAMS();
dispParams.cArgs = 0;
dispParams.cNamedArgs = 0;
object pVarResult;

System.Runtime.InteropServices.ComTypes.EXCEPINFO excepInfo = new System.Runtime.InteropServices.ComTypes.EXCEPINFO();

nRetVal = idisp.Invoke(nIds[0], ref guid, 0, (ushort)System.Runtime.InteropServices.ComTypes.INVOKEKIND.INVOKE_PROPERTYGET, ref dispParams, out pVarResult, ref excepInfo, null);

// Launching a function with parameters
object[] oArgs = new object[]{ 10 };
nRetVal = idisp.GetIDsOfNames(ref guid, new string[] { "GetUserPreferenceIntegerValue" }, 1, 0, nIds);
dispParams.cArgs = 1;
--> dispParams.rgvarg = ???; <-- Here, I must provide a IntPtr object that represent the array "oArgs" defined above.
dispParams.cNamedArgs = 0;
dispParams.rgdispidNamedArgs = new object[] { };
nRetVal = idisp.Invoke(nIds[0], ref guid, 0, (ushort)System.Runtime.InteropServices.ComTypes.INVOKEKIND.INVOKE_FUNC, ref dispParams, out pVarResult, ref excepInfo, null);

Thanks!

Re: How to call a COM function with arguments using IDispatch in C#

chrismisztur15-Jun-10 11:01

chrismisztur

15-Jun-10 11:01

Hi JF.

I'm on an IDispatch path as well with Solidworks.

See my post: https://forum.solidworks.com/thread/34206?tstart=0[^]

Have you gotten any further on this ?

Chris
fixitchris @solidworks forum

tips on windows application running on a local server

mrkeivan6-Apr-10 7:33

mrkeivan

6-Apr-10 7:33

Hey guys,
I'm writing a windows application which is going to be run on a local server and accessed by around 5, 10 clients.
I'm using visual studio 2008 + SQL Server 2005
I wanted to get some tips before I start coding, like how to figure out sqlserver connection should I use IP or server name what is best method of configuring the database, cause this isn't meant for one place and I don't want to customize it every time I want to install it in a new place.
and also any other hint that might come handy in the future, if u got any links, tutorials, etc that would be great.

Thanx
K1

Re: tips on windows application running on a local server

Not Active6-Apr-10 8:48

Not Active

6-Apr-10 8:48

mrkeivan wrote:
should I use IP or server name

Either will work.

mrkeivan wrote:
if u got any links, tutorials, etc that would be great.

How about this one, www.codeproject.com

I know the language. I've read a book. - _Madmatt

Re: tips on windows application running on a local server

Dave Kreskowiak6-Apr-10 9:58

Dave Kreskowiak

6-Apr-10 9:58

Your questions aren't really answerable because the "best" solution depends entirely on how your app is designed, what it's supposed to be doing, your data model, how you want to handle concurrency issues, ... You're asking about coding when you haven't even sat down and layed out the requirements for the app yet.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

Re: tips on windows application running on a local server

mrkeivan6-Apr-10 18:31

mrkeivan

6-Apr-10 18:31

that is exactly what I'm looking for, up to now I have always worked on win application on single computer, this is my first experience with app on network, if u ve got any articles, sites or anything that can guide me, that would be superb.

regards,

Re: tips on windows application running on a local server

PIEBALDconsult6-Apr-10 11:43

PIEBALDconsult

6-Apr-10 11:43

mrkeivan wrote:
any other hint that might come handy in the future

Yes, as I said earlier, write a Web Service, perhaps with Windows Communication Foundation.

http://www.codeproject.com/Messages/3428795/coding-for-a-software-which-is-gonna-run-on-a-serv.aspx[^]

datagridview

hamid53056-Apr-10 6:45

hamid5305

6-Apr-10 6:45

hi every one in world of codeproject !
Q) How can i add datagridview in a special column of another datagridview?
for exp:
i wanna to add another datagridview to dgvTell.columns[0] :
something like this :
dgvTell.columns.Add(another datagridview);

efrew

Re: datagridview

RCoate6-Apr-10 13:15

RCoate

6-Apr-10 13:15

Um, you could try doing a google/bing/whatever search for "Nested Datagridview".
That will even give you the codez.

i am getting an error in C#.

amitk_1896-Apr-10 6:17

amitk_189

6-Apr-10 6:17

Class not Registered (Exception from HRESULT:0x80040154(REGDB_E_CLASSNOTREG))
how should i solve this...

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.