Re: Dispose an instance - C# Discussion Boards

4-Mar-09 2:11

Hi,
I created an dll and create an instance of that dll in my application. After the use of this instance i need to dispose it. How can i do so?

Thankyou
YP

DaveyM694-Mar-09 2:14

DaveyM69

4-Mar-09 2:14

If the object in question has a close or dispose method then call that. If not, once it's no longer referenced by any active objects, it will automatically be cleaned up when the garbage collector next runs. You can sometimes help matters by making the instance = null.

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

Xmen Real 4-Mar-09 4:21

Xmen Real

4-Mar-09 4:21

yes but some classes needs to be dispose...like Graphics

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DaveyM694-Mar-09 4:35

DaveyM69

4-Mar-09 4:35

Which is why it has a Dispose method Big Grin | :-D

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

harold aptroot4-Mar-09 6:29

harold aptroot

4-Mar-09 6:29

Did you mean you loaded the dll into the appdomain manually?
If so, you can't unload it. You must make a new domain and load it into that one, and destroy the new domain when needed.

yesu prakash4-Mar-09 18:37

4-Mar-09 18:37

Hi,
I have a dll called dllexample.dll, a public function called 'demofunction' in it

i reffer the dllexample.dll to my form and allocate 'demofunction'

demofunction df = new demofunction();

after some time i need to kill the 'df', also need to allocate again if requried

This is the real requirement..

Thankyou

harold aptroot4-Mar-09 22:46

harold aptroot

4-Mar-09 22:46

That sounds very normal - no AppDomains required. Just do what the others suggested (let the GC take care of it or implement IDisposable)

yesu prakash5-Mar-09 17:23

5-Mar-09 17:23

it still not working....

code in my dll

private bool disposed = false;
public void Dispose(bool disposing)
{
if (!disposed)
{
if (disposing)
{}
disposed = true;
}
}
public void Dispose()
{ Dispose(true);
GC.SuppressFinalize(this);
}
~ListenDesktop()
{
Dispose(false);
}

in my form :
------------

ListenDesktop lt = new ListenDesktop()
lt.Dispose();

but still the 'lt' is active.
I dont need 'lt' no longer in my form.. how can i solve it?

passing multiple parameters to the query in C#

harold aptroot5-Mar-09 22:37

harold aptroot

5-Mar-09 22:37

I'm not sure..
You could use FxCop to check it - it will make a warning if it isn't correct.

Deepali Khalkar4-Mar-09 1:34

Deepali Khalkar

4-Mar-09 1:34

I have tried with the following parameterised query for select statement and is working fine.

SqlCeConnection conn;
SqlCeCommand comm;
comm = new SqlCeCommand();
comm.Connection = conn;
comm.CommandText = "select * from signuptbl where username =@uname";
SqlCeParameter para = new SqlCeParameter();
para.ParameterName = "@uname";
para.Value = textBox1 .Text ;
comm.Parameters.Add(para);

Now i want to write an update query which takes multiple parameters. I have thought of the following code.

SqlCeConnection conn;
SqlCeCommand comm;
comm = new SqlCeCommand();
comm.Connection = conn;
comm.CommandText = "update signuptbl set firstname=@fname,lastname=@lname,,psw=@psw1 where username =@uname";
SqlCeParameter para = new SqlCeParameter();
para.ParameterName = "@uname";
para.Value = textBox1 .Text ;
comm.Parameters.Add(para);
para.ParameterName = "@psw";
para.Value = textBox2 .Text ;
comm.Parameters.Add(para);
para.ParameterName = "@fname";
para.Value = textBox3 .Text ;
comm.Parameters.Add(para);
para.ParameterName = "@lname";
para.Value = textBox3 .Text ;
comm.Parameters.Add(para);

I have tried this code but the row was not updated.
Is this a proper way? How to pass multiple parameters in a query? Can i get a sample code for the same.

Thanks in advance.. Smile | :)

N a v a n e e t h4-Mar-09 1:42

N a v a n e e t h

4-Mar-09 1:42

You have created only one parameter and overwriting it's properties each time. You need separate SqlCeParameter instances for each parameter.

comm.Parameters.AddWithValue("@uname",textBox1 .Text);
comm.Parameters.AddWithValue("@psw",textBox2 .Text);
...

AddWithValue[^] will create SqlCeParameter internally and add it to the Parameters collection.

Smile | :)

Navaneeth

How to use google | Ask smart questions

Megidolaon4-Mar-09 2:04

Megidolaon

4-Mar-09 2:04

An easy way is to only pass one string that is the full query.
You simply construct it by using variables in C# to read the input and then adding it to the query string.
You might have to add brackets and commas to the query string after the variables have been added.

J4amieC4-Mar-09 2:29

J4amieC

4-Mar-09 2:29

Worst answer you could have given, you've just told the OP to take aa step backwards to dynamically-built sql queries rather than using parameters.

You should read up on SQL Injection attacks.

fly9044-Mar-09 5:14

fly904

4-Mar-09 5:14

In most of my code I pass the parameters as a variable to another function which would make the code look like this:

SqlCeParameter[] sqlParams = new SqlCeParameter[4];

sqlParams[0] = new SqlCeParameter("@uname", textbox1.Text);
...

comm.Parameters.AddRange(sqlParams);

hmmm pie

TcpChannel disconnect

yesu prakash4-Mar-09 0:15