Re: SQL querying problem - C# Discussion Boards

C# "for example desktop icon"(object) drag and drop method

Renven6-Nov-09 1:38

6-Nov-09 1:38

Hi,

Lets supose i have C# application witch gets object position in desktop (for example "icon" or "shotcut") coordinates (x,y).
I need method whitch uses coordinates from application (x,y, and x_put, y_put) take object from one position and DRAG and DROP that objet to other position. Also it would be great if that methot can WORK FAST.

I appretiate your help,

Re: C# "for example desktop icon"(object) drag and drop method

Richard MacCutchan6-Nov-09 2:34

Richard MacCutchan

6-Nov-09 2:34

Lots of information here[^].

Telnet/pop3..........??

Hum Dum6-Nov-09 1:33

Hum Dum

6-Nov-09 1:33

I created an small pop3 application(with help of articles present here) to retrieve emails, its working for small emails. But when it comes to large emails say 5 MB+ it stuck.

Can't able to retrieve whole data from pop3 server.

I tried check thru telnet also, but it also got stuck in infinite loop, and continue to remian same.

Can any one plz help me, how to retrieve whole message from pop3 ?

So that i can strip whole message.

regards

SQL querying problem

Emmet_Brown6-Nov-09 0:52

Emmet_Brown

6-Nov-09 0:52

Hi!

I'm trying to check my database if an entry on a field is already exists in the DB.

My Sql command is this:

string Sqlcommand = "SELECT Name FROM Students WHERE Id LIKE '" + TextBox1 + "'";

and I'm executing this as follows

SqlCeCommand com = new SqlCeCommand(Sqlcommand, conn);
SqlCeDataAdapter da = new SqlCeDataAdapter(com);

after these, just to be sure, I want to check if the query returned some rows or not
what should I do?

note: I've tried these ->

DataSet s = new DataSet();
da.Fill(s);
if( s == null)
if( s.Tables.Count == 0)
if( da == null)

can anybody help? :/

Message Closed

6-Nov-09 1:09

stancrm

6-Nov-09 1:09

Message Closed

modified 23-Nov-14 7:19am.

Re: SQL querying problem

Emmet_Brown6-Nov-09 1:22

Emmet_Brown

6-Nov-09 1:22

Oh THANK YOU!

but now it started to give an error
da.Fill(s) says
SqlCeException was unhandled
There was an error parsing the query. [ Token line number = 1, Token line offset = 61, Token in error =)]

I don't know why, this line did not give an error just 5 minutes ago, I erased new codes and still it gives an error

what should I do? :/

Message Closed

6-Nov-09 1:33

stancrm

6-Nov-09 1:33

Message Closed

modified 23-Nov-14 7:19am.

Re: SQL querying problem

Emmet_Brown6-Nov-09 1:42

Emmet_Brown

6-Nov-09 1:42

well it seems like a bug, but this is a very simple action to encounter a bug, maybe I should ask in a seperate topic

thank you for your answers Big Grin | :-D

Re: SQL querying problem

Emmet_Brown6-Nov-09 1:52

Emmet_Brown

6-Nov-09 1:52

I found that I just made a stupid syntax error in my SQL command Big Grin | :-D

thank you, my problem is solved Big Grin | :-D

oh the code project, you're a saint

Re: SQL querying problem

sravsk15-Dec-09 21:12

sravsk

15-Dec-09 21:12

Hi
{
using (SqlCeConnection ceConn = new SqlCeConnection("Data Source=" + (System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase)) + "\\Northwind.sdf; Persist Security Info=False"))
{

ceConn.Open();

SqlCeException was unhandled
There was an error parsing the query. [ Token line number = 1, Token line offset = 61, Token in error =)]

I don't know why, this line did not give an error just 5 minutes ago, I erased new codes and still it gives an error

what should I do?

sravanthi veerisetti

Re: SQL querying problem

Nicholas Butler6-Nov-09 2:00

Nicholas Butler

6-Nov-09 2:00

You should probably also read this:

SQL Injection Attacks and Some Tips on How to Prevent Them[^]

Nick

----------------------------------
Be excellent to each other Smile | :)

Re: SQL querying problem

Calla6-Nov-09 2:36

Calla

6-Nov-09 2:36

Maybe you're screwing up the SQL if you add '" + TextBox1 + "' instead of '" + TextBox1.Text + "'

Re: SQL querying problem

Emmet_Brown6-Nov-09 3:15

Emmet_Brown

6-Nov-09 3:15

Thank y'all Big Grin | :-D

Re: SQL querying problem

Md. Marufuzzaman6-Nov-09 7:09

Md. Marufuzzaman

6-Nov-09 7:09

Try the following......

Function:

<PRE>
string strSqlQuery= "SELECT Name FROM Students WHERE Id LIKE '" + TextBox1 + "%'";

object retValue;
            try
            {
                  ObjSqlCommand = new SqlCommand(strSqlQuery, ObjSqlConnection);
                  ObjSqlConnection.Open();
                  retValue = ObjSqlCommand.ExecuteScalar();

            }
            catch (Exception ex)
            {
                  return (object)ex.Message.ToString();
            }
            finally
            {
                  ObjSqlConnection.Close();
                  ObjSqlCommand = null;
                  ObjSqlConnection= null;
                  strSqlQuery = null;

            }
   return retValue;
</PRE>

Thanks
Md. Marufuzzaman

Don't forget to click [Vote] / [Good Answer] on the post(s) that helped you.

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Transferring items from a listbox to a string variable [modified]

gamer11276-Nov-09 0:34

gamer1127

6-Nov-09 0:34

Hello. I'm having a little problem transferring all the items in the listbox to a string variable. All the items in the listbox are also string type so i don't have any problems about data types. I tried to use array of string type variable but when i transfer them using a for..loop statement it gets a run-time error that the index was out of bounds. How will I resolve that? How can i store all the items into a variable without selecting them? I used the listbox as a control for outputs.

this is the code:

for (int a = 0; a < lstBoxRequests.Items.Count; a++)
                {
                    string[] passedRequests = new string[a];

                    passedRequests[a] = Convert.ToString(lstBoxRequests.Items[a]);

                    MessageBox.Show(passedRequests[a]);
                }

modified on Friday, November 6, 2009 6:41 AM

Re: Transferring items from a listbox to a string variable

Covean6-Nov-09 1:03

Covean

6-Nov-09 1:03

Try this:

string[] passedRequests = new string[lstBoxRequests.Items.Count];
for (int a = 0; a < lstBoxRequests.Items.Count; a++)
                {
                    

                    passedRequests[a] = Convert.ToString(lstBoxRequests.Items[a]);

                    MessageBox.Show(passedRequests[a]);
                }

Greetings
Covean

Re: Transferring items from a listbox to a string variable

Eddy Vluggen6-Nov-09 1:14

Eddy Vluggen

6-Nov-09 1:14

How manu elements are there in your array? And how many elements would the loop go through?

If your array holds 10 items, then a for-next loop will go from either 1 to 10 or from 0 to 9. Your loop goes 11 times, starting at passedRequest[0] and moving on to passedRequst[10], generating an "index out of bounds". That means that the number between the [] is smaller or larger then the number of items in the array Smile | :)

for (int a = 0; a < lstBoxRequests.Items.Count -1; a++)

Next item is that you're reinitializing the array on each loop. That means that the entire Array is created anew, with a new maximum-upperbound of "a". You'd prolly want a maximum number in the array that corresponds to the number of items in the combobox. That would come to something like this;

int itemCount = lstBoxRequests.Items.Count -1;
string[] passedRequests = new string[itemCount];
for (int a = 0; a < itemCount; a++)
{
    passedRequests[a] = Convert.ToString(lstBoxRequests.Items[a]);

There are easier ways to enumerate through the items, but I'll leave that to the next poster Smile | :)

I are Troll Suspicious | :suss:

Re: Transferring items from a listbox to a string variable

V.6-Nov-09 1:27

6-Nov-09 1:27

I think you'll miss one item with this code.

Eddy Vluggen wrote:
for (int a = 0; a < lstBoxRequests.Items.Count -1; a++)

or do this:

for (int a = 0; a <= lstBoxRequests.Items.Count -1; a++)

or this:

for (int a = 0; a < lstBoxRequests.Items.Count; a++)

V.

Stop smoking so you can: Enjoy longer the money you save.
Moviereview Archive

Re: Transferring items from a listbox to a string variable

Covean6-Nov-09 1:29

Covean

6-Nov-09 1:29

for (int a = 0; a < lstBoxRequests.Items.Count; a++)

Is right, your loop:

for (int a = 0; a < lstBoxRequests.Items.Count - 1; a++)

is wrong it leaves one item alone!

General:

for(int loop=0; loop < count; loop++) or for(int loop=0; loop <= count -1; loop++)!

His problem was the following:

for (int a = 0; a < lstBoxRequests.Items.Count; a++)
                {
                    string[] passedRequests = new string[a];

                    passedRequests[a] = Convert.ToString(lstBoxRequests.Items[a]);   <---- this causes the out of array, because passedRequests.length = a but passedRequests[a] is wrong !!!

                    MessageBox.Show(passedRequests[a]);
                }

Edit: Second problem was the creation of the string array in the loop.

Greetings
Covean

Re: Transferring items from a listbox to a string variable

Eddy Vluggen6-Nov-09 2:12

Eddy Vluggen

6-Nov-09 2:12

Covean wrote:
or (int a = 0; a < lstBoxRequests.Items.Count - 1; a++)
is wrong it leaves one item alone!

You're right, I was wrong. I've been looking at these too much;

for(int x = 0; x <= bla.Count - 1; x++)

Notice that the check has an equals-sign. The current project that I'm working has both styles mixed throughout the code. In VB6 Smile | :)

I are Troll Suspicious | :suss:

Re: Transferring items from a listbox to a string variable

V.6-Nov-09 2:18

6-Nov-09 2:18

Eddy Vluggen wrote:
In VB6

that explains it Big Grin | :-D

V.

Stop smoking so you can: Enjoy longer the money you save.
Moviereview Archive

Drag rectangle using mouse in C#

lexical16-Nov-09 0:31

lexical1

6-Nov-09 0:31

Hi..if sumone knows how to do it plz help i m a beginner in C#.
i have made the reactangle don't know how to drag it with the help of mouse and redraw it where i release the mouse button..

private void Shapes_Paint(object sender, PaintEventArgs e)<br />
      {<br />
            if (Square.Checked == true)<br />
            {<br />
                e.Graphics.DrawRectangle(Pens.Red, 180, 80, 80, 80);<br />
             }<br />
             if (Triangle.Checked == true)<br />
             {<br />
                  e.Graphics.DrawPolygon(Pens.Red, new Point[] {  <br />
                  new Point   (300, 150), new Point(400, 250), new Point<br />
                  (200, 250) });<br />
             }<br />
      }

if i click mouse buton while the mouse is on top of the square, and then holds the mouse button down and drags the mouse, then the square will be dragged by the mouse:

1. As the square is being dragged, the mouse pointer should
remain over the same point on the square as it was when the
mouse was initially clicked. As the mouse is moving, the
square should move continuously with the mouse.
2. If the user clicks the left mouse button with the mouse
outside of the square and then drags the mouse, the square
should not move, even if the mouse is dragged over the
square.

Re: Drag rectangle using mouse in C#

Luc Pattyn6-Nov-09 3:18

Luc Pattyn

6-Nov-09 3:18

Hi,

this is the scheme; items marked OPT are optional (they show the object in a different style while dragging):

1) add class members to keep track of rect position, hit position, ...
OPT: provide a bool "dragging"

2) inside MouseDown:
store mouse position
calculate and store hit position (the point going to be dragged around)
OPT: set dragging true and call Invalidate()

3) inside MouseMove:
calculate and store new rect position
call Invalidate()

4) inside Paint:
draw rectangle based on stored rect position (do NOT use Control.MousePosition)
OPT: the way it is drawn (color, line thickness, ...) may depend on dragging

5) inside MouseUp:
OPT: set dragging false and call Invalidate()

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Re: Drag rectangle using mouse in C#

lexical18-Nov-09 21:35

lexical1

8-Nov-09 21:35

Hi..!!
i understand the above points but don't know how to add class members and how to calculate the positions and store them..

what i know is that i have to use 'e' like e.X, e.Y but don't know the proper way for this..

can sumone help me plzz....

Re: Drag rectangle using mouse in C#

Luc Pattyn8-Nov-09 23:10

Luc Pattyn

8-Nov-09 23:10

hina123tariq wrote:
don't know how to add class members

yes you do. Inside a class, but not inside any method, add lines such as private int mouseX;

hina123tariq wrote:
how to calculate the positions

some positions may be absolute (i.e. top left of the screen is 0,0); most positions are relative to their container (i.e. top left of the Control or Form is 0,0). Hence what it takes most often is one addition or one subtraction. Make a little drawing to help yourself.

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

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