Show a ProgressBar while uploading a picture (Windows Form C#)

问题

I have a situation here. I have a picture box in windows form and i let user to browse a picture by using openfileupload control and after that i set selected picture into picture box. Here is my code:

namespace Employee_Card_Manager
{
public partial class Form1 : Form
{
    string Chosen_File = "";

    public Form1()
    {
        InitializeComponent();
    }

    private void label1_Click(object sender, EventArgs e)
    {

    }

    private void openFileDialog1_FileOk(object sender, CancelEventArgs e)
    {

    }

    private void button1_Click(object sender, EventArgs e)
    {
        selectpic.Title = "Browse Employee Picture!";
        selectpic.InitialDirectory = System.Environment.GetFolderPath(Environment.SpecialFolder.Personal);
        selectpic.FileName = "";
        selectpic.Filter = "JPEG Images|*.jpg|GIF Images|*.gif|BITMAPS|*.bmp";

        if (selectpic.ShowDialog() != DialogResult.Cancel)
        {
            progressBar1.Enabled = true;
            Chosen_File = selectpic.FileName;
            pictureBox1.Image = Image.FromFile(Chosen_File);
            progressBar1.Enabled = false;
        }
    }
}

}

It is working perfectly! I need to add some modification to this code so that when user browse a picture and presses Open button my application will show him a progress bar that this picture is being uploaded in mean time... I have found the following code to show a progress bar:

namespace ProgressBarSampleCSharp
{
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void CreateButton_Click(object sender, EventArgs e)
    {
        ProgressBar pBar = new ProgressBar();
        pBar.Location = new System.Drawing.Point(20, 20);
        pBar.Name = "progressBar1";
        pBar.Width = 200;
        pBar.Height = 30;

        //pBar.Dock = DockStyle.Bottom;

        pBar.Minimum = 0;
        pBar.Maximum = 100;
        pBar.Value = 70;

        Controls.Add(pBar);
    }
}

}

But i have no idea how to fit this code into my class so that it will show progress bar in the mean time when picture is being uploaded! any ideas??

回答1:

If it truly is taking a long time to 'upload' you could use the FileSystemWatcher's changed event. Every time it is fired you increment the progressbar some fraction of the total known file size.

回答2:

I have an old code adapted to answer your question.
I let the ProgressBar control out of the InitializeComponent just for clarity.
However, I think that when you run this code, you'll remove the progress bar completely.

namespace Employee_Card_Manager 
{ 
    public partial class Form1 : Form 
    { 
        ProgressBar pBar = new ProgressBar(); 
        string Chosen_File = ""; 

        public Form1() 
        { 
            InitializeComponent(); 
            CreateProgressBar();
        } 
        private void CreateProgressBar() 
        { 
            pBar.Location = new System.Drawing.Point(20, 20); 
            pBar.Name = "progressBar1"; 
            pBar.Width = 200; 
            pBar.Height = 30; 
            pBar.BackColor = Color.Transparent;
            pBar.Minimum = 0; 
            pBar.Maximum = 100; 
            pBar.Value = 0; 
            Controls.Add(pBar); 
        } 

        private void button1_Click(object sender, EventArgs e) 
        { 
            selectpic.Title = "Browse Employee Picture!"; 
            selectpic.InitialDirectory = System.Environment.GetFolderPath(Environment.SpecialFolder.Personal); 
            selectpic.FileName = ""; 
            selectpic.Filter = "JPEG Images|*.jpg|GIF Images|*.gif|BITMAPS|*.bmp"; 

            if (selectpic.ShowDialog() != DialogResult.Cancel) 
            { 
                Chosen_File = selectpic.FileName; 
                pictureBox1.LoadCompleted += new AsyncCompletedEventHandler(pictureBox1_LoadCompleted);
                pictureBox1.LoadProgressChanged += new ProgressChangedEventHandler(pictureBox1_LoadProgressChanged);
                pictureBox1.WaitOnLoad = false;
                pictureBox1.LoadAsynch(Chosen_file);
            } 
        } 

        private void pictureBox1_LoadCompleted(object sender, AsyncCompletedEventArgs e)
        {
            pBar.Value = 0;
        }

        private void pictureBox1_LoadProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            pBar.Value = e.ProgressPercentage;
        }    
    }
} 

来源：https://stackoverflow.com/questions/9445669/show-a-progressbar-while-uploading-a-picture-windows-form-c