C#

if(obj==null)
{
    //do some action
}

Class Employee
{
    String FirstName;
    String LastName;

    public bool IsEmpty()
    {
        if(!String.IsNullOrEmpty(FirstName) || !String.IsNullOrEmpty(LasttName))
            return False;
        else
            return True;
    }
}

public interface IEmpty
{
    bool IsEmpty { get; }
}

public static bool IsNullOrEmpty<T>(T obj) where T : IEmpty
{
    if (obj == null)
        return true;
    return obj.IsEmpty;
}

public class IntString : IEmpty
{
    private string text;
    private int value;

    public IntString()
        : this(0, string.Empty)
    { }
    public IntString(int value)
        : this(value, string.Empty)
    { }
    public IntString(string text)
        : this(0, text)
    { }
    public IntString(int value, string text)
    {
        this.text = text;
        this.value = value;
    }

    public string Text
    {
        get { return text; }
        set { text = value; }
    }
    public int Value
    {
        get { return value; }
        set { this.value = value; }
    }

    // Interface implementation
    public bool IsEmpty
    {
        get { return value == 0 && string.IsNullOrEmpty(text); }
    }
}

IntString intString = new IntString();
Console.WriteLine(IsNullOrEmpty<IntString>(intString));

Object objVariable;
if(!String.IsNullOrEmpty(objVariable))

Object objVariable;
if(objVariable !=null && objVariable.ToString() !="")

internal static class UtilityMethods
{
    internal static bool IsEmpty(this object o)
    {
        return o == null;
    }
}

Object objVariable;
if(!objVariable.IsEmpty())
{
    // bla!
}

I are Troll

///
/// This class extends the the DataGridView so row numbers will
/// automatically appear in the row header cells. In this
/// implementation, the width of the column that contains the row
/// header cells is automatically adjusted to accomodate the row
/// numbering.
///
class MyDGV : DataGridView
{
    public MyDGV()
    {
        //perform any necessary customization initialization here

    } //end default constructor

    protected override void OnRowPostPaint(DataGridViewRowPostPaintEventArgs e)
    {
      //this method overrides the DataGridView's RowPostPaint event
      //in order to automatically draw numbers on the row header cells
      //and to automatically adjust the width of the column containing
      //the row header cells so that it can accommodate the new row
      //numbers,

        //store a string representation of the row number in 'strRowNumber'
        string strRowNumber = (e.RowIndex + 1).ToString();

        //prepend leading zeros to the string if necessary to improve
        //appearance. For example, if there are ten rows in the grid,
        //row seven will be numbered as "07" instead of "7". Similarly, if
        //there are 100 rows in the grid, row seven will be numbered as "007".
        while (strRowNumber.Length < this.RowCount.ToString().Length) strRowNumber = "0" + strRowNumber;

        //determine the display size of the row number string using
        //the DataGridView's current font.
        SizeF size = e.Graphics.MeasureString(strRowNumber, this.Font);

        //adjust the width of the column that contains the row header cells
        //if necessary
        if (this.RowHeadersWidth < (int)(size.Width + 20)) this.RowHeadersWidth = (int)(size.Width + 20);

        //this brush will be used to draw the row number string on the
        //row header cell using the system's current ControlText color
        Brush b = SystemBrushes.ControlText;

        //draw the row number string on the current row header cell using
        //the brush defined above and the DataGridView's default font
        e.Graphics.DrawString(strRowNumber, this.Font, b, e.RowBounds.Location.X + 15, e.RowBounds.Location.Y + ((e.RowBounds.Height - size.Height) / 2));

        //call the base object's OnRowPostPaint method
        base.OnRowPostPaint(e);
    } //end OnRowPostPaint method
} //end class

double prev;
double dim1;

private void txtDim1_Leave(object sender, EventArgs e)
{
    prev = dim1;
    dim1 = ValidateEntry(txtDim1);

    if (dim1 != 0.0 & prev != dim1)
    {
        MessageBox.Show("Event Fired");
    }

}

private double ValidateEntry(TextBox MyTextBox)
{
    try
    {
        return Double.Parse(MyTextBox.Text);
    }
    catch (FormatException ex)
    {
        MessageBox.Show("Enter a valid numeric value" + ex.Message);
        MyTextBox.Focus(); return 0.0;
    }
}

private void txtDim1_KeyPress(object sender, KeyPressEventArgs e)
{
    if (e.KeyChar == 13) { txtDim2.Focus(); }
}