Was ist ein PostBack

Konkretes Problem

protected void Page_Load(object sender, EventArgs e)
{
    FirstnameTextBox.Text = "Norbert";
    LastnameTextBox.Text = "Eder";
}

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        FirstnameTextBox.Text = "Norbert";
        LastnameTextBox.Text = "Eder";
    }
}

Lebenszyklen

Fazit

public class ExifReader
{
    public string ReadExifDate(Image image)
    {
        PropertyItem[] items = image.PropertyItems;
        foreach (PropertyItem pi in items)
        {
            if (pi.Id == 306)
            {
                string val = 
                    System.Text.Encoding.Default.GetString
                        (pi.Value);
                return val;
            }
        }
        return "n/a";
    }
}

this.ContentPlaceHolder.Controls.Clear();
this.ContentPlaceHolder.Controls.Add
    (
    LoadControl("modules/TestControl.ascx")
    );