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Hi everyone,
I have an application that should support two types of databases (SQL Server and Oracle). What I want to do is create a datalayer that will use SqlConnection or OracleConnection object depending on the database.
In C++ I would have done the following:
template<class ConnectionType>
class DataLayer
{
...
...
ConnectionType * type
}
DataLayer<SqlConnection> m_layer; // for example
How can I achieve the same result in C#?
Thanks,
Sincerely,
Pankaj
Without struggle, there is no progress
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You would use the provider pattern, an abstract class or interface that contains the methods you would invoke. You then use the appropriate implementation (SQL, Oracle, whatever) that you could configure in the application's .config file. We've been using this since .NET 1.0 for our smart client application.
.NET 2.0 will use the provider pattern heavily: for database access, authentication, personalization, and much, much more.
For more information, you should read a couple of recent MSDN articles:
Microsoft MVP, Visual C#
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Thanks Heath!
Pankaj
Without struggle, there is no progress
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Hi. I need 3 applications working at the same time. The first one is a
Pocket PC application, the second is a web service and the third one isn't
done yet. This third app is only to receive messages (maybe a Windows Forms
application or even an ASP.NET one...)
The question is how to send messages to the third application. It should be
the web service when the Pocket PC calls a web method. How could I do that?
Remoting? I only need to send a string, so the easier method 
Regards,
Diego F.
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.NET Remoting is probably the easiest way. The PPC (presumably a .NET CF application) would call the web service method, which calls a remoting method on the third application. It should be tollerant that the third application might not be running, especially if this is an application that must be started by the user (like a desktop application monitor or something).
Microsoft MVP, Visual C#
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OK, then I'll try with Remoting. Is there any consideration I should know using Remoting with web services or is just the same way as using Remoting between two console applications?
Regards,
Diego F.
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You should be mindful of the service registration type. If you use a singleton - depending how the remoting object is hosted, yours calls may be synchronous while web service methods are not. This will result in synchronous-like method calls to your web service. The lifetime of the remoting object is also a factor. Basically, there's a lot of factors that go into this. If you're not familiar with .NET Remoting, I suggestion a couple of books. I just posted these earlier today, so I'll just refer you to that post[^].
Microsoft MVP, Visual C#
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Hi,
I have a combobox and now i want that you can see the first item when it's filled. Now it's empty and you can type in the combobox.
Thx!
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You should change the DropDownStyle property to ComboBoxStyle.DropDownList. The default is DropDown and allows you type, where DropDownList doesn't. If you want the user to be able to type in new items, then you should set the SelectedIndex to 0.
Microsoft MVP, Visual C#
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Hello,
I have a xml-file where some words are in uppercase. Is it possible to edit the entire file. So everything in the file is in lowercase?
thx in advance
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Read the entire file into a String, just like any text file, then call the .ToLower method on the String, then write the new file out to a DIFFERENT file. Write it out a different file just to make sure nothing went wrong and you still have the original file to work from.
RageInTheMachine9532
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While the two previous answers tell you how, I want to stress the "why and why not". If the XML elements and attributes are supposed to be a certain case, you should leave them. XML elements and attributes are case-sensitive. Changing them would cause any processors specific to that schema (like an XSLT or DOM parser) to fail (at least, identifying it as the appropriate doc type).
If this is a file you have created, then you must make sure that any processing is changed to use the lower-case elements and attributes.
Microsoft MVP, Visual C#
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hi
why output of this code isn't Transparent.
Bitmap b = new Bitmap(100,20);<br />
Graphics g = Graphics.FromImage(b);<br />
g.Clear(Color.Transparent);<br />
g.DrawString("Test",new Font("Tahoma",8),new SolidBrush(Color.Green),0,0);<br />
b.Save("test.gif",System.Drawing.Imaging.ImageFormat.Gif);<br />
Close();<br />
thanks.
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A GIF is an index image, so there is no transparent color. There is, however, a color that is masked so that the GIF appears transparent. See the Bitmap.MakeTransparent method. You provide it a color and that image is saved with that color's index marked as the transparent color so it appears transparent when displayed.
Microsoft MVP, Visual C#
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Hi i am trying to get the value of an attribute displayed, but i can't seem to find the best way to get to it. If the element contains no attributes it returns -1?
XmlDocument document = new XmlDocument();<br />
document.Load("..\\..\\commands.xml");<br />
<br />
XmlNodeReader reader = new XmlNodeReader(document);<br />
<br />
this.Show();<br />
<br />
while (reader.Read())<br />
{<br />
switch (reader.NodeType)<br />
{<br />
case XmlNodeType.Element:<br />
int attributes = reader.AttributeCount;<br />
cmdOutput.Text += "<" + reader.Name + reader.GetAttribute(attributes) + ">";<br />
break;<br />
case XmlNodeType.Text:<br />
cmdOutput.Text += "\t" + reader.Value + "\r\n";<br />
break;<br />
case XmlNodeType.EndElement:<br />
cmdOutput.Text += "</" + reader.Name + ">\r\n";<br />
break;<br />
}<br />
}
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Why not just have a case for the XmlNodeType.Attribute? Your switch cases will be called appropriately so even if you were to just write-out the attribute, it will happen in between XmlNodeType.Element and XmlNodeType.Text or XmlNodeType.EndElement, if there are any attributes. What you have anyway will not work anyway. AttributeCount - 1 would be the index of the last attribute. Remember that indexes in the .NET FCL are 0-based.
Microsoft MVP, Visual C#
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Hello,
Is there a way to sort an xml with xslt faster? Right now a file with 15 records takes about 9 seconds. A file with 60 records takes about 15 seconds. I probably won't have more then 60 records but a file with 1000 records takes about 2 minutes. 15 seconds is still a little to long i think, is it possible to make it faster?
Thx in advance
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How is the sorting being done? Through code you wrote or through an for-each order-by?
RageInTheMachine9532
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Hi,
i did it like this:
private void SortXml(string sortOrder, string sortString)
{
xml.Load(filePath);
string pad = "//session[@name='" + cboSessions.SelectedItem.ToString() + "']";
XmlNodeList selectedNode = xml.SelectNodes(pad);
string box = selectedNode.Item(0).OuterXml;
xml.LoadXml(box);
XmlTextWriter xmltw = new XmlTextWriter(hulpfilePath,new UTF8Encoding(false));
xml.WriteTo(xmltw);
xmltw.Close();
string xsl = "<xsl:stylesheet version=\"1.0\" xmlns:xsl=\"http://www.w3.org/1999/XSL/Transform\">"
+ "<xsl:template match=\"@*|node()\">"
+ "<xsl:copy>"
+ " <xsl:apply-templates select=\"@*|node()\">"
+ "<xsl:sort data-type=\"number\"" + " select=\""+ sortString +"\"" + " order=\"" + sortOrder + "\"" + "/>"
+ "</xsl:apply-templates>"
+ "</xsl:copy>"
+ "</xsl:template>"
+ "</xsl:stylesheet>";
XslTransform xslt = new XslTransform();
StringReader rdr = new StringReader(xsl);
xslt.Load(new XPathDocument(rdr), null,null);
xslt.Transform(hulpfilePath,hulpfilePath,null);
ds.Clear();
ds.ReadXml(hulpfilePath);
File.Delete(hulpfilePath);
}
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Since your having an XSL stylesheet do the sorting for you, there isn't really a way to get a significant speed increase. The only thing I can think of trying is loading the XML document and writing the sort yourself, shuffling around nodes using you own sort algorithm. But I don't know if your going to get the kind of performance your looking for. You could only try it and see.
I haven't had the cause to sort an XML file myself. I usually just get the data I need and have the visual control sort it as needed.
RageInTheMachine9532
"...a pungent, gastly, stinky piece of cheese!" -- The Roaming Nome
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i did it like appelz did it
thx for the help
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Hello,
I want to open a file for my program. I'm doing it with the openfiledialog but my file can also be on a server. How can i get that file then? Is it possible?
thx in advance
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OpenFileDialog Op=new OpenFileDialog();
Op.ShowDialog();
System.Diagnostics.Process.Start(Op.FileName.ToString());
Sreejith S S Nair
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It depends on how you can access that server. If you access the file through a UNC, the OpenFileDialog can do that and most classes in the .NET FCL can use UNC paths. If it's an HTTP path, the OpenFileDialog can reference the file if you have the HTTP server in your Network Locations "directory", but most classes that deal with files won't be able to access it. You'd have to use a WebClient or something to download it first.
One agnostics way would be to use a WebRequest to request the file using the file path. If it's a local or UNC file path, a FileWebRequest is returned. If it's an HTTP URL, an HttpWebRequest is returned.
Really, though - you don't need to care. WebRequest.GetResponse returns a WebResponse which you can use to "download" (copy to local) the file and then you can work on it however you want. The WebRequest/WebResponse classes are pluggable protocols, and you can find out more information about them in the .NET Framework SDK under the System.Net namespace.
Microsoft MVP, Visual C#
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