public void DoSmth(ref int nRefVar){}

or

public void DoSmth(out int nOutVar){}

What's the difference? Well, that's pretty easy. To pass a variable by reference, first you have create that reference by initializing the variable. Usually you want to use this way when you're gonna use the value of the variable inside the function.

public void DoSmth(ref int nRefVar)
{
if (nRef > 10)
nRef = 5;
else
nRef = 25;
}
int nRefVar = 10;
DoSmth(ref nRefVar);

To pass a variable as an out parameter you have only to declare it first. This way is just for getting the value. Usually you will need it when you have to get more than one return value from a procedure.

public void DoSmth(out int nOutVar1, out int nOutVar2)
{
nOutVar1 = 1;
nOutVar2 = 2;
}
int nOutVar1, nOutVar2;
DoSmth(out nOutVar1, out nOutVar2);

Good Luck

For those who looks for a new job

1. Explain the life cycle of an ASP .NET page.
2. Explain the .NET architecture.
3. What are object-oriented concepts?
4. How do you create multiple inheritance in c# and .NET?
5. When is web.config called?
6. Differences between DLL and EXE?
7. Can an assembly have EXE?
8. Can a DLL be changed to an EXE?
9. Compare & contrast rich client (smart clients or Windows-based) & browser-based Web application
10. Compare Client server application with n-Tier application
11. Can a try block have more than one catch block?
12. Can a try block have nested try blocks?
13. How do you load an assembly at runtime?
14. If I am writing in a language like VB or C++, what are the procedures to be followed to support .NET?
15. How do you view the methods and members of a DLL?
16. What is shadowing?
17. What are the collections you’ve used?
18. What is a static class?
19. What is static member?
20. What is static function?
21. What is static constructor?
22. How can we inherit a static variable?
23. How can we inherit a static member?
24. Can we use a static function with a non-static variable?
25. How can we access static variable?
26. Why main function is static?
27. What is garbage collection?
28. Can we force garbage collector to run?
29. What is reflection?
30. What are different type of JIT?
31. What are Value types and Reference types?
32. What is concept of Boxing and Unboxing?
33. What’s difference between VB.NET and C#?
34. What’s difference between System exceptions and Application exceptions?
35. What is CODE Access security?
36. What is a satellite assembly?
37. How to prevent my .NET DLL to be decompiled?
38. What’s the difference between Convert.toString and .toString() method ?
39. What is Native Image Generator (Ngen.exe)?
We have two version of the same assembly in GAC? I want my client to make choice which assembly to choose?
40. What is CodeDom?

 
using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.IO;
using System.Diagnostics;    
 
// some code goes here
// ..................
// ...................    
 
string strResult = string.Empty;
// first of all the file should be uploaded
// let's use the UploadFile procedure from the previous article
string strFileName = string.Empty;
string strBaseFolder = "c:\uploads";
string strFolder = Path.Combine(strBaseFolder, Guid.NewGuid().ToString());
bool bIsOk;
try
{
	bIsOk = UploadFile(FileInputControl, strFolder, ref strFileName);
}
catch
{
	bIsOk = false;
}    
 
if (bIsOk)
{
	// getting full file path
	string strFilePath = Path.Combine(strFolder, strFileName);    
 
	// here we should set connection parameters (i.e. they could be taken from web.config)
	string strServerName = "", strDBName = "", strUserName = "", strPassword = "";    
 
	// executing entire script
	using (Process proc = new Process())
	{
		proc.StartInfo.FileName = "osql";
		proc.StartInfo.Arguments = string.Format("/S {0} /U {1} /P {2} /d {3} /i {4}",
			strServerName, strUserName, strPassword, strDBName, strFilePath);
		proc.StartInfo.UseShellExecute = false;
		proc.StartInfo.RedirectStandardOutput = true;
		proc.StartInfo.RedirectStandardError = true;
		proc.StartInfo.CreateNoWindow = true;
		try
		{
			proc.Start();
			proc.WaitForExit();
			strResult = proc.StandardOutput.ReadToEnd();
			proc.Close();
		}
		catch
		{
			strResult = @"The script can not be executed.
                                           Make sure there is osql utility on the server.";
		}
	}    
 
	// now lets delete the file as we don't want it to be saved on the server
	Directory.Delete(strFolder, true);
}
else
{
	strResult = "The file cannot be uploaded to the server";
}    
 
// now we could display strResult variable containg information about script execution
// i.e. using Response.Write method
Page.Response.Write(strResult);

Good luck!

 
using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.IO;    
 
public class MyPage : Page
{
..........
    // strUploadFolder - full path to the folder in which we are gonna store the file (i.e c:\savehere)
    // strFileName - return parameter, that will store upaded file's name
    // function returns true if uploading has been successfull, otherwise we get false
    protected bool UploadFile(HtmlInputFile fileinput, string strUploadFolder, ref string strFileName)
    {
        HttpPostedFile myFile = fileinput.PostedFile;
        int nFileLen = myFile.ContentLength;
        strFileName = string.Empty;
        if (nFileLen > 0)
        {
            byte[] myData = new byte[nFileLen];
            myFile.InputStream.Read(myData, 0, nFileLen);
            strFileName = Path.GetFileName(myFile.FileName);    
 
            try
            {
                if (!Directory.Exists(strUploadFolder))
	       Directory.CreateDirectory(strUploadFolder);
                using (FileStream newFile = new FileStream(Path.Combine(strUploadFolder, strFileName),
                                       FileMode.Create))
	   {
	       newFile.Write(myData, 0, myData.Length);
	       newFile.Close();
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
            return true;
        }
        else
            return false;
    }
..........
}

 
IF NOT EXISTS
	(SELECT * FROM syscolumns
	WHERE id = OBJECT_ID(N'[MyTable]') AND name = 'MyColumn')
             ALTER TABLE dbo.MyTable ADD MyColumn INT

Enjoy!

 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Collections;
using System.Collections.Specialized;
 
namespace ClassLibrary
{
    public class QueryStringBuilder
    {
        protected NameValueCollection m_QueryString;
 
        public QueryStringBuilder(NameValueCollection nvcQueryString)
        {
            m_QueryString = new NameValueCollection(nvcQueryString);
        }
 
        // static function returning a new querystring with a new parameter
        public static NameValueCollection QSWithParameter(NameValueCollection nvcCurrentQS,
                                                      string strParameterName, string strParameterValue)
        {
            NameValueCollection nvcQS = new NameValueCollection(nvcCurrentQS);
 
            for (int i = 0; i < nvcQS.Count; i++)
            {
                if (nvcQS.GetKey(i) == null)
                {
                    nvcQS.Remove(null);
                    break;
                }
            }
            if (nvcQS.GetValues(strParameterName) == null)
                nvcQS.Add(strParameterName, strParameterValue);
            else
                nvcQS[strParameterName] = strParameterValue;
            return nvcQS;
        }
 
        // function returning a new querystring with a new parameter
        public NameValueCollection QSWithParameter(string strParameterName, string strParameterValue)
        {
            return QSWithParameter(m_QueryString, strParameterName, strParameterValue);
        }
 
        // static function returning a querystring without a parameter
        public static NameValueCollection QSWithoutParameter(NameValueCollection nvcCurrentQS,
                                                                               string strParameterName)
        {
            NameValueCollection nvcQS = new NameValueCollection(nvcCurrentQS);
            if (nvcQS.GetValues(strParameterName) != null)
                nvcQS.Remove(strParameterName);
            return nvcQS;
        }
 
        // function returning a querystring without a parameter
        public NameValueCollection QSWithoutParameter(string strParameterName)
        {
            return QSWithoutParameter(m_QueryString, strParameterName);
        }
 
        // static function returning url with a querystring
        public static string UrlWithQueryString(NameValueCollection nvcQueryString, string strUrl)
        {
            int nQS = strUrl.IndexOf("?");
            if (nQS > -1)
                strUrl = strUrl.Substring(0, nQS);
            if (nvcQueryString.Count > 0)
            {
                for (int i = 0; i < nvcQueryString.Count; i++)
                {
                    strUrl += String.Format("{0}{1}={2}", i == 0 ? "?" : "&", nvcQueryString.Keys[i],
                                                                                    nvcQueryString[i]);
                }
            }
            return strUrl;
        }
 
        // static function returning RawUrl with a querystring
        public static string UrlWithQueryString(NameValueCollection nvcQueryString)
        {
            return UrlWithQueryString(nvcQueryString, HttpContext.Current.Request.RawUrl);
        }
 
        // function returning url with a current querystring
        public string UrlWithQueryString(string strUrl)
        {
            return UrlWithQueryString(m_QueryString, strUrl);
        }
 
        // function returning RawUrl with a current querystring
        public string UrlWithQueryString()
        {
            return UrlWithQueryString(m_QueryString);
        }
 
        // procedure removing a parameter from a current querystring
        public void RemoveQSParameter(string strParameterName)
        {
            m_QueryString = QSWithoutParameter(strParameterName);
        }
 
        // procedure adding a parameter to a current querystring
        public void SetQSParameter(string strParameterName, string strParameterValue)
        {
            m_QueryString = QSWithParameter(strParameterName, strParameterValue);
        }
    }

Have a look at the following example:

 
<fieldset class="form-fieldset">
    <label class="textbox surname">
        <span>Surname</span>
<input name="surname" id="surname" type="text" />
    </label>
</fieldset>

Now with a help of CSS we could access any element of this form. Very flexible. We could use as many fieldsets as we could wish. We could even have fieldsets inside fieldsets.

Alright. Later I started thinking how I could use that for simplify the way of creating asp.net web forms. So I created a class FieldSet

 
    public class FieldSet : HtmlGenericControl
    {
        public FieldSet()
            : base("fieldset")
        { }
 
        public FieldSet(string strLegend)
            : this()
        {
            HtmlGenericControl legend = new HtmlGenericControl("legend");
            Controls.Add(legend);
            legend.InnerText = strLegend;
        }
 
        // as an example I have created this simple method which allows add a new input text to the fieldset
        public HtmlInputText AddInputText(string strLabel, string strCSSClass)
        {
            HtmlInputText txt = new HtmlInputText();
            AddControl(strLabel, txt, strCSSClass);
            return txt;
        }
 
        public HtmlInputText AddInputText(string strLabel)
        {
            return AddInputText(strLabel, null);
        }
 
        // this method is used for adding any web contol to the fieldset
        public void AddControl(string strLabel, Control cntrl, string strCSSClass)
        {
            HtmlGenericControl label = new HtmlGenericControl("label");
            Controls.Add(label);
            label.Controls.Add(new LiteralControl("<span>" + strLabel + "</span>"));
            if (strCSSClass != null)
                label.Attributes["class"] = strCSSClass;
 
            label.Controls.Add(cntrl);
            cntrl.ID = ID + "_cntrl_" + Controls.Count.ToString();
            label.Attributes["for"] = cntrl.ClientID;
        }
 
        public void AddControl(string strLabel, Control cntrl)
        {
            AddControl(strLabel, cntrl, null);
        }
    }

So now while developing another asp.net web-form I just could write the code:

 
.....
FieldSet fs = new FieldSet("Editing surname");
Controls.Add(fs);
HtmlInputText txtSurname = fs.AddInputText("Surname:", "surname");
.....

See? Just three lines of code.

The script has its parameters:

SET @BOPrefix = 'C' - - Prefix of the business object
SET @TablePrefix = 'dt_' - - Table prefix if it has any
SET @TableName = 'dt_Customer' -- Table for wich we need to generate the business object
SET @CurrentNamespace = 'BusinessObjects' - - A namespace in which we are gonna create the business object
SET @ReplacePKWithID = 1 - - In case we have a primary key field named CustomerID but in the business oject we wanna replace it with 'ID'
SET @IDPropertyName = 'ID' - - The name of the field we are gonna use to rename ID column in the business object

I have attached the script to this post.

files: Generating Business Objects

The parameters I need to modify are:

SET @ProcedurePrefix = 'usp_' -- prefix of the sproc (kinda usp_GetEmployee)
SET @TablePrefix = '' -- table prefix, if a table has a prefix (dt_)
SET @TableName = 'dt_Employee'
SET @IncludeTabulation = 1 -- are we gonna generate paginating and sorting staff (see previous post)
SET @CreateSaveAndAddTogether = 0 -- there is an option to generate one sproc for inserting and updating

This script has its limitation though. Currently a table for wich we are going to generate sprocs has to have an integer primary key.

files: Generate Sprocs