C#

WebRequest request = WebRequest.Create(webaddress);
               HttpWebResponse response = (HttpWebResponse)request.GetResponse();
               HttpStatusCode code = response.StatusCode;
               responseString = code.ToString();

System.NullReferenceException: Object reference not set to an instance of an object.
  at web_check.Service1.getStatusCode(String webaddress)

HttpWebResponse response = (HttpWebResponse)request.GetResponse();

public Form1()
{
    InitializeComponent();

    for (int i = 1; i <= 2; i++)
    {
        // Get the "A" combobox
        string name = string.Format("comboBoxA{0}", i);

        // Get reference to the combobox using the name
        ComboBox cbo = (ComboBox)this.Controls[name];

        // Set the tag property to the index of this combobox
        cbo.Tag = i.ToString();

        // Assign an event handler to that comboboxes SelectedIndexChanged event
        cbo.SelectedIndexChanged += new EventHandler(this.ComboBoxA_SelectedIndexChanged);
    }
}

private void ComboBoxA_SelectedIndexChanged(object sender, EventArgs e)
{
    // Get reference to the combobox that caused this event to fire
    ComboBox cboA = (ComboBox)sender;

    // Get the index out of its tag property.  This is so we know how to find the associated "B" combobox
    string index = cboA.Tag.ToString();

    // Get the "B" combobox
    ComboBox cboB = (ComboBox) this.Controls[string.Format("comboBoxB{0}", index)];

    // Set the selected index of the "B" comboBox to the "A" comboBox
    cboB.SelectedIndex = cboA.SelectedIndex;

}

private void adapterSelect(object sender, EventArgs e) {
    //// Create references to original comboboxes
    ComboBox cbServ = (ComboBox)sender;
    ComboBox cbAdp = (ComboBox)this.Controls[string.Format("slot{0}Adp", cbServ.Tag.ToString())];

    // This line returns the null exception
    cbAdp.Text = "test";
}

Q: Why can't I serialize .NET Framework classes like exceptions and fonts? 

baranils wrote:

You give me a way by pointing out some documentation usefull to read

williamnw wrote:

Can you tell me how to use google?

<br />
Microsoft.Office.Interop.Excel.Application excelApplication = null;<br />
            Microsoft.Office.Interop.Excel.Workbook workbook = null;<br />
            Microsoft.Office.Interop.Excel.Worksheet worksheet = null;<br />
<br />
            excelApplication = new Microsoft.Office.Interop.Excel.Application();<br />
            excelApplication.Visible = false;<br />
<br />
            workbook = excelApplication.Workbooks.Open(@"D:\Après\mailing_RA_20090219.xls", 0, false, 5, "", "", false, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "", true, false, 0, true, false, false);<br />
            worksheet = (Microsoft.Office.Interop.Excel.Worksheet)workbook.Worksheets[2];<br />
<br />
<br />
<br />
<br />
            excelApplication.Quit();<br />
            excelApplication = null;<br />
<br />
            string cellValue = "";<br />
            object cellObject = null;<br />
            Microsoft.Office.Interop.Excel.Range range = null;<br />
<br />
<br />
            range = (Microsoft.Office.Interop.Excel.Range)worksheet.Cells[3,2];<br />
<br />
            cellObject = range.get_Value(null);<br />
            cellValue = (cellObject == null ? "" : cellObject.ToString().Trim());<br />
<br />
<br />
            Console.WriteLine(cellValue);<br />