Adding class values - C# Discussion Boards

Larry Antram2-Dec-03 14:25

2-Dec-03 14:25

This is probably a dumb question, but I'm trying to figure out how to add a row to an SQL table using C# -- without having to create a messy INSERT command.

For example, in ASP/JScript I can do something like this:

con = Server.CreateObject( "ADODB.Connection" );
con.Open( "CONNECT_STRING" );
   
    rs = Server.CreateObject( "ADODB.Recordset" );
    rs.CursorLocation = adUseClient;
    rs.Open( "TABLE_NAME", con, adOpenKeyset, adLockOptimistic, adCmdTable );
    
        rs.AddNew();
        rs( "COLUMN_NAME" ) = COLUMN_VALUE;
        rs( "COLUMN_NAME" ) = COLUMN_VALUE;
        ... etc ...
        rs.Update();
        rs.Close();
    
    con.Close();

In C++, using these ADO classes[^], I can do something like this:

CADODatabase db;
if( db.Open( "CONNECT_STRING" )
{
    CADORecordSet rs( &db );
    if( rs.Open( "TABLE_NAME", CADORecordSet::openTable ) )
    {
        rs.AddNew();
        rs.SetFieldValue( "COLUMN_NAME", COLUMN_VALUE );
        rs.SetFieldValue( "COLUMN_NAME", COLUMN_VALUE );
        ... etc ...
        rs.Update();
        rs.Close();
    }
    db.Close();
}

I'm trying to learn how to do this in C#, and I've got this so far (okay, not much):

SqlConnection sql = new SqlConnection( "CONNECT_STRING" );
SqlCommand cmd = new SqlCommand( "COMMAND", sql );
cmd.ExecuteNonQuery();

I assume this would work, but as mentioned, I don't want to be burdened with creating a huge complicated INSERT command or escaping the ' character in fields. I'd rather just set the individual fields to some sort of object (like I've done with ADO Recordset in the past) and then use that to add a row to the table.

Can anyone point me in the right direction? Any idea what classes I need to use to do this? Or a rough overview of the procedure?

Re: Adding a row to SQL table using C#

Heath Stewart2-Dec-03 16:43

Heath Stewart

2-Dec-03 16:43

You're not using the SQL statements correctly in .NET if you think INSERTs (or any other command) is hard. Take a look at the documentation for SqlParameter and SqlCommand.Parameters. You don't have to worry about properly escaping param values and can work with input, output, and return params with no problem:

SqlConnection conn = new SqlConnection(connectionString);
try
{
  SqlCommand cmd = conn.CreateCommand();
  cmd.CommandText = "INSERT INTO MyTable (ID, Name, Birthday) " +
    "VALUES(@ID, @Name, @Birthday)";
  cmd.Parameters.Add("@ID", SqlDbType.Int);
  cmd.Parameters.Add("@Name", SqlDbType.NVarChar, 40);
  cmd.Parameters.Add("@Birthday", SqlDbType.DateTime);
  string[] names = new string[] {"Dad", "Mom", "Brother"};
  conn.Open();
  for (int i=0; i<names.Length; i++)
  {
    cmd.Parameters["@ID"].Value = i;
    cmd.Parameters["@Name"].Value = names[i];
    cmd.Parameters["@Birthday"].Value = DateTime.Now.AddYears(i * -10);
    cmd.ExecuteNonQuery();
  }
}
finally
{
  if (conn != null) conn.Close();
}

This is just an example to show you the power of parameterized statements. The same is done with SqlCommands when using the SqlDataAdapter.

The other way is to create a DataSet, build the schema (or create a strongly-typed DataSet using VS.NET's DataSet designer (or other data designers, like dragging and dropping a table from the connections tab), or the xsd.exe utility), and add rows to that, which you then call SqlDataAdapter.Update, but you'll still need parameterized queries.

This is how ADO.NET works and - if you architect your solution right - can be much better than the old ADO way (for example, DataSets are very good at tracking changes, dealing with relationships, and even identity columns).

-----BEGIN GEEK CODE BLOCK-----
Version: 3.21
GCS/G/MU d- s: a- C++++ UL@ P++(+++) L+(--) E--- W+++ N++ o+ K? w++++ O- M(+) V? PS-- PE Y++ PGP++ t++@ 5 X+++ R+@ tv+ b(-)>b++ DI++++ D+ G e++>+++ h---* r+++ y+++
-----END GEEK CODE BLOCK-----

Re: Adding a row to SQL table using C#

Larry Antram2-Dec-03 16:59

Larry Antram

2-Dec-03 16:59

Thank you! That is exactly what I wanted to know. Big Grin | :-D

Any idea on this problem

Alex Korchemniy2-Dec-03 13:18

Alex Korchemniy

2-Dec-03 13:18

I have a working printtemplate but css print formating isn't working.

I have a CSS style page-break-after: always; set for div. When i open the page in IE and go to print preview the css styles work right. Using my print template the pagebreak setting doesn't work. How do i force IE to process CSS properly?

Re: Any idea on this problem

Heath Stewart2-Dec-03 16:57

Heath Stewart

2-Dec-03 16:57

You can't force IE to do anything. You must work within the constraints of the software. That said, remember that print templates wrap the body of a document to be printed. Depending on how you scope the styles in your CSS document. The best way is to examine the HTML that is generated and see why the style isn't being used. If you're setting this for element hierarchies, remember that those might not be valid after inserting the body content between other elements in your print template.

Also, are you specifying page-breaks only for the print @media? If so, make sure that in your <IE:DEVICERECT> you specify MEDIA="print", otherwise it will default to the screen styles.

Control clipping

Gary Kirkham2-Dec-03 10:38

Gary Kirkham

2-Dec-03 10:38

I am developing a user control and I want the ability to resize the control outside the borders of its parent (could be another control or a form). An example of this is the dropdown list on a combo box. Just setting the parent of the control to be the form doesn't handle the case where the control wants to go off the form.

What is the best way to do this?

Gary Kirkham

A working Program is one that has only unobserved bugs

I thought I wanted a career, turns out I just wanted paychecks

Re: Control clipping

Alex Korchemniy2-Dec-03 11:04

Alex Korchemniy

2-Dec-03 11:04

You have to place your control in a toplevel window - since you want to have this go beyond the form.

First thing you will need to do is make a class "TopLevelWindow" derive it from "Form". You have to set the appropriate styles you want, so that it doesn't show in taskbar and doesn't have any borders. You then use the windows api SetWindowPos(...) to position the window. From there its fairly easy. You just have to include what ever you need in the popup window. Create a popup manager class that takes a control and puts it into the toplevelwindow.

Adding class values

MrEyes2-Dec-03 7:32

MrEyes

2-Dec-03 7:32

Apologies if the title of this thread is a little vague.

Let me explain a little further, lets assume that I have the following simple class :

public class MyClass
{
 public int x;
 public MyClass(int x)
 {
   this.x = x
 }
}

Now elsewhere in code, I create multiple instances of this class :

MyClass mc1 = new MyClass(16);
MyClass mc2 = new MyClass(11);
MyClass mc3 = new MyClass(73);

What I would like to be able to do is add all the values in the current objects of a class to get a total. Forexample :

int ClassTotal = myClass.GetTotals();

Which in this example would return 100 (i.e. 16 + 11 + 73)

This also needs to be smart enough to handle the fact that an object may have been disposed, so if I was to dispose the object mc3, GetTotals would return 27

post.mode = signature;
SELECT everything FROM everywhere WHERE something = something_else;
> 1 Row Returned
> 42

Re: Adding class values

ankita patel2-Dec-03 8:20

ankita patel

2-Dec-03 8:20

create a static variable "ClassTotal" in your class.

add the code to add the value of the new instance of the class to the ClassTotal in the constructor and add the code to subtract the value of the desposed instance in the destructor.

Problems calling a COM+ component

Ivan Fernandez2-Dec-03 7:07

Ivan Fernandez

2-Dec-03 7:07

Hi,
I've got a problem, calling via remoting, a COM+ which activation is type library. I configure the client application and the web.config file, then I make the call, and that's ok. The problem appears because my COM+ application has to read information from a configuration file. My first attempt to solve this, was to introduce this information in the web.config file, but it doesn't work. The fact is that the configuration file which it's been read is aspnet_wp.exe.config, instead web.config.
I am creating the COM+ through a wrapper. When I call the wrapper, it is executed in one AppDomain, but when the wrapper creates the instance of the component, the AppDomain is changed to the Default AppDomain, changing also the configuration file used.
I hope to give enough information (and understable!!!;P) If you need further information, please, don't hesitate asking me.

Thanks,

Ivan.

Iván Fernández

Re: Problems calling a COM+ component

Bruce Duncan2-Dec-03 8:08

Bruce Duncan

2-Dec-03 8:08

I don't think what you are trying to do is possible. As far as I know, .config files can only be used with applications (theapp.exe.config) or ASP.NET (web.config).

You would find that if your COM+ application used Server (as opposed to Library) Activation, to config file that the .NET framework would try to load would be dllhost.exe.config.

I assume one could try to force the .NET classes used to read the configuration to load the info from a specific file, but I've never used them myself (I don't even know which are used Blush | :O

)

If anyone knows any better, or if I am talking rubbish, please correct me. Smile | :)

Searching the web without Google is like straining sewage with your teeth.
Userfriendly, 2003/06/07

Re: Problems calling a COM+ component

Ivan Fernandez2-Dec-03 8:16

Ivan Fernandez

2-Dec-03 8:16

I can't use the COM+ application like Server because I don't want to have any dll in the GAC. I want to use probing to indicate where my application has to search for the asssemblies.
I could use another file to read the configuration information, like you said, but the probing information, as far as I know, has to be in the application config file.

Any other suggestion??

Thanks!!

Iván Fernández

Re: Problems calling a COM+ component

Heath Stewart2-Dec-03 8:56

Heath Stewart

2-Dec-03 8:56

What it comes down to is the CLR host. The ASP.NET host is hardcoded to use the Web.config file as its configuration file. The executable loader by default uses yourapp.exe.config. In your case, it's odd that aspnet_wp.exe.config is being used.

In any case, if you are using a wrapper, perhaps your wrapper has a chance to create the AppDomain that hosts the COM+ service itself? If so, when you are configuring the AppDomain, you can specify any .config file you want so long as the CLR can resolve the location. See AppDomain.SetupInformation for more details.

video conference

notaclue2-Dec-03 4:58

notaclue

2-Dec-03 4:58

How do I allow my web visitors to:
video conference, create private rooms, exchange
files much like "MSN Messenger" but embedded in my
web page?

Moving a file from one server to another

chubbysilk2-Dec-03 4:12

chubbysilk

2-Dec-03 4:12

Hello,
I am trying to implement an asp.net page which will move a file from a folder on the web server to another server. I have the following code:

File.Move("E:\temp\image.gif", "\\dnssvr1\Ad\image.gif");

When I try this, I am getting some sort of error about a username and password. Is there a particular place where I have to set a username and password? Do I need to specify the path to the destination differently?

Thanks,
RC

Re: Moving a file from one server to another

Heath Stewart2-Dec-03 4:32

Heath Stewart

2-Dec-03 4:32

This means you (or whatever credentials the app is running under) don't have permissions to the remote resource. Either make sure your domain account has appropriate permissions to that directory (or, in some cases, that a local user with exactly the same username and password exists on both machines - such as on a workgroup), or use impersonation for someone that does. See WindowsIdentity for easy impersonation in .NET.

GDI - Creating Images

MrEyes2-Dec-03 3:31

MrEyes

2-Dec-03 3:31

I am looking to create a class that uses given paramaters will generate an image, the resulting image is then fired into a picture box and the world is happy.

Problem is all the GDI (ish) tutorials I have come across assume that I am generating the images within the actual form that displays them and not an external class.

Is there a way of achieving this?

As an example, I have the following code in my form :

picturebox1.Image = new MyEllipse(200);

And this code in my class :

public Image MyEllipse(int height)
{
//ellipse generatation code here
return img;
}

post.mode = signature;
SELECT everything FROM everywhere WHERE something = something_else;
> 1 Row Returned
> 42

Re: GDI - Creating Images

Heath Stewart2-Dec-03 4:05

Heath Stewart

2-Dec-03 4:05

You're not looking at the right tutorials, then. The principal is the same, though - you need a surface to draw on. So create a bitmap and use the Graphics device to draw on it:

Bitmap bmp = new Bitmap(32, 32);
Graphics g = Graphics.FromImage(bmp);
g.FillRectangle(new SolidBrush(Color.White), 0, 0, 32, 32); // White background
// continue with more.
g.Dispose();
return bmp;

See the Bitmap and Graphics class documentation for more details and sample code.

Re: GDI - Creating Images

MrEyes2-Dec-03 7:25

MrEyes

2-Dec-03 7:25

Thankyou very much

That is exactly what I needed, I am now inundated with a myriad of dynamic pie charts

post.mode = signature;
SELECT everything FROM everywhere WHERE something = something_else;
> 1 Row Returned
> 42

need source code

Member 5581242-Dec-03 3:09

Member 558124

2-Dec-03 3:09

hi
Can anyOne send me the source code of Flow Diagram or like this software.
Flow Diagram is a softWare that we used it for drawing flowchart or other like DFD or ERD Diagrams.
Best Regards
Alireza Meshkin

Re: need source code

Christian Graus2-Dec-03 10:37

Christian Graus

2-Dec-03 10:37

Sure - I've got some under the desk here.....

Actually, I believe there is a free library that does this kicking around. But this forum is really for programmers, not people looking for freebies, so you'll have to google it.

Christian

I have drunk the cool-aid and found it wan and bitter. - Chris Maunder

Saving nodes in a TreeView to an XML file?

thomasa2-Dec-03 2:53

thomasa

2-Dec-03 2:53

I'm struggeling a bit here.
I'm trying to save a TreeView and all of it's nodes as shown in the code belowe:

xw.WriteStartElement("TreeView");
foreach(TreeNode tn in theTreeView.Nodes)
{
xw.WriteStartElement("TreeNode");
xw.WriteAttributeString("Text", tn.Text);
if(theNode.Parent == null)
{
xw.WriteAttributeString("Parent", "null");
foreach(TreeNode n in tn.Nodes)
{
xw.WriteStartElement("TreeNode");
xw.WriteAttributeString("Text", n.Text);
xw.WriteAttributeString("Parent", n.Parent.ToString());
xw.WriteEndElement();
}
}
xw.WriteEndElement();
}
xw.WriteEndElement();

The xml file looks something like this:
<treeview>
- <treenode text="Startnode" parent="null">
<treenode text="Node0" parent="TreeNode: Startnode">
<treenode text="Node3" parent="TreeNode: Startnode">
<treenode text="Node4" parent="TreeNode: Startnode">

- <treenode text="Node5" parent="null">
<treenode text="Node6" parent="TreeNode: Node5">

The problem is that I only get the first nodes and the second nodes in the TreeView hirarki. If I continue to add a foreach(TreeNode n in theNode.Nodes) I will end up writing it forever...

Is there a better way of getting all the nodes in the TreeView than
foreach(TreeNode n in tn.Nodes)?

or what must I do?

Thanks in advance for your help Rose | [Rose]

,
Thomas

Re: Saving nodes in a TreeView to an XML file?

Heath Stewart2-Dec-03 4:00

Heath Stewart

2-Dec-03 4:00

You have heard of recursion, right?

private const string xmlns = "urn:myTree";
private const string prefix = "t";
public void WriteToXml(TreeView view)
{
  XmlTextWriter writer = new XmlTextWriter("somefile.xml", Encoding.UTF8);
  writer.WriteStartDocument();
  writer.WriteStartElement(prefix, "treeView", xmlns);
  foreach (TreeNode node in view.Nodes)
    this.WriteToXmlHelper(node, writer);
  writer.WriteEndElement();
  writer.WriteEndDocument();
}
private void WriteToXmlHelper(TreeNode node, XmlTextWriter writer)
{
  writer.WriteStartElement(prefix, "treeNode", xmlns);
  writer.WriteStartAttribute(prefix, "text", xmlns);
  writer.WriteString(node.Text);
  writer.WriteEndAttribute();
  foreach (TreeNode node in node.Nodes)
    this.WriteToXmlHelper(node, writer);
  writer.WriteEndElement();
}

Recursion is the best way of handling hierarchical data. This example also writes out a hierarchical XML structure which is easier to resolve then following IDREFs and what not (since it looks like you're venturing down that road).

XML Comments

Colin Angus Mackay2-Dec-03 0:39

Colin Angus Mackay

2-Dec-03 0:39

Hi,

Does anyone know of a good XML Comment documentation tool that allows custom xml elements. I am looking to include things like history information (you know author, date/time, reason). I've looked at NDoc which produces great output but doesn't seem to handle custom XML elements and is full of bugs.

Regards,
Colin.

--Colin Mackay--

"In the confrontation between the stream and the rock, the stream always wins - not through strength but perseverance." (H. Jackson Brown)

Re: XML Comments

Heath Stewart2-Dec-03 3:41

Heath Stewart

2-Dec-03 3:41

The most popular free tool is NDoc, which yours truly also works on. Smile | :)

(And I'm not just saying it's the most popular because I do work on it - look at the companies that use it!)

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