Resize WinForm Controls Automatically

Let' say you have a form with a ListBox and OK and Cancel buttons.
 

You want controls to be resized automatically when a form is resized. This is how you can achieve this by using the Anchor property:

Place all controls inside a GroupBox. Set the Anchor and Dock properties

GroupBox properties:
Anchor : Top, Bottom, Left, Right
Dock : None

Buttons properties:
Anchor : Bottom, Right
Dock : None

ListBox properties:
Anchor : Top, Bottom, Left, Right
Dock : None

Save Window Position in Registry

This is how you could save a Window position in the Registry so that the Window position could be restored next time the Form loads.


Declare the following constant strings:

 public const string REGKEY = @"SOFTWARE\MyCompany\MyApp\"; 

public const string WINWIDTH = "windowWidth";

public const string WINHEIGHT = "windowHeight";

Then, create a key for your application in the Registry. 
Declare a RegistryKey variable:
private RegistryKey key;

Use the following method to obtain the key:

public RegistryKey GetKey(string RegKey)

{

            RegistryKey Key = Registry.CurrentUser.OpenSubKey(RegKey, true);

            if (Key == null)

            {

                Key = Registry.CurrentUser.CreateSubKey(RegKey);

            }

            return Key;

}

key =  GetKey(REGKEY);

Get window width and height:

int width = Form1.Size.Width;

int height = Form1.Size.Height;

Save window width and height in the registry and close the RegistryKey.

key.SetValue(WINWIDTH, width);

key.SetValue(WINHEIGHT, height);

key.Close(); 

When you load your form, read the values from the registry:

width = Convert.ToInt16 (key.GetValue(WINWIDTH));

height = Convert.ToInt16 (key.GetValue(WINHEIGHT));

Set the new window size:

Form1.Size = new Size(width, height);

Concise Code to Enable/Disable WinForm Controls

Let's say you have a check box (cb1)  on a form that enables a text box (txt1)  and disables a listbox (lst1).  You can write a statement that shows this dependency on 2 lines:

  txt1.Enabled = cb1.Checked;

  lst1.Enabled = !cb1.Checked;

This works fine. However, we repeat the reference to the check box state twice.
There is a way to write the above statements on the same line:

   lst1.Enabled = !(txt1.Enabled = cb1.Checked);

Looks simple when you get it right. But it took me a few minutes to figure it out.

Examine Columns in ASP.NET Dynamic Data MetaTable

This is how you get access to all columns in a MetaTable that serves as a data source to your controls like a DetailsView or a GridView. Dynamic Data generates the following code for each ASP.NET page by default:

   protected MetaTable table;

   protected void Page_Load(object sender, EventArgs e)

   {

       table = DetailsDataSource.GetTable();

       Title = table.DisplayName;

   }

The MetaTable class has a Columns property that returns a collection of MetaColumns for the table. This allows us to enumerate through the collection and check for any custom attributes on table columns:

    

   foreach (MetaColumn column in table.Columns)

   {

      if (column.Attributes.OfType<MyCustomAttribute>().Count() > 0)

          ......

      }

   }

This is based on a tip found at this blog.

Reverse .NET SortedList

 This post shows how you could reverse a SortedList in C# by its keys:

SortedList<string, string> strlist = new SortedList<string, string>();

strlist.Add("f3", "xxx");

strlist.Add("f1", "ccc");

strlist.Add("f2", "aaa");

foreach (KeyValuePair<string, string> kvp in strlist)

{

    Console.WriteLine("Key = {0}, Value = {1}", kvp.Key, kvp.Value);

}           

Console.WriteLine("reverse the list");

IEnumerable<KeyValuePair<string, string>> revList = strlist.Reverse();

foreach (KeyValuePair<string, string> kvp in revList)

{

    Console.WriteLine("Key = {0}, Value = {1}", kvp.Key, kvp.Value);

}

Open a Text File If It Is Used by Another Process

Use the FileStream class's Open method to open a file with FileShare.ReadWrite as a parameter. Then use StreamReader class supplying the FileStream object as a constructor argument:

FileStream fs = File.Open(filename, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);

StreamReader sr = new StreamReader(fs);

Set Instance Property Value through Reflection

This is how you can set object property value using reflection:

Employee emp = new Employee();
PropertyInfo pi = emp.GetType().GetProperty("myPropertyName");

pi.SetValue(emp, "myValue", null);

This is how you read a value:

string value = pi.GetValue(emp, null);

To access all properties of an object:

foreach (PropertyInfo info in emp.GetType().GetProperties()){
    ....
}

Using reflection you can automatically populate a transfer object from a database record if the object property names and types are the same as the record names and types.

An example using a DataReader:

List <employee>list = new List <employee>();
while (dataReader.Read())
{
Employee emp = new Employee();
foreach (PropertyInfo info in emp.GetType().GetProperties())
{
   if (!DBNull.Value.Equals(dr[info.Name]))
      info.SetValue(emp, dr[info.Name], null);
}
list.Add(emp);
}
 

The resulting list will hold Employee records.