C# Discussion Boards - CodeProject

Fill Combobox with Large amount of Data

29-Dec-12 21:30

See here[^].

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Nabawoka29-Dec-12 3:17

29-Dec-12 3:17

i have more than 55000 Customer and i wanna Fill Combobox with this customers quick .. there is any way
to load form quickly and to enter Combobox quickly
** i use background worker but this hang my form and my app is run slowly can i use threading and how
i want solutin plz

 private void backWork_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Cancelled)
            {
            }
            else
            {
               FillComboBox();
               cmb3ameelname.Focus();
               Loadform = true;
               cmb3ameelname.SelectedItem = null;
               cmbLandTele.SelectedItem = null;
            }
        }

 private void backWork_DoWork(object sender, DoWorkEventArgs e)
        {
            CusLis = CustomerManger.SelectCustomersAll();
        }


void FillComboBox()
    {
      cmbameelname.DataSource = CusLis;
      cmbameelname.DisplayMember = "CustName";
     cmbameelname.ValueMember = "CustId";
   }

frm_load()
   {
       this.backWork.DoWork += new DoWorkEventHandler(this.backWork_DoWork);

        this.backWork.RunWorkerCompleted+=new RunWorkerCompletedEventHandler(this.backWork_RunWorkerCompleted);

      this.backWork.RunWorkerAsync();
   }

Eddy Vluggen29-Dec-12 3:36

Eddy Vluggen

29-Dec-12 3:36

Mohamed Nabawy wrote:
have more than 55000 Customer and i wanna Fill Combobox with this customers

That's a little bit "too much" to be useful as a dropdown-list. I strongly recommend a popup with a datagridview.

Mohamed Nabawy wrote:
. there is any way

to load form quickly and to enter Combobox quickly

Databinding is usually a bit slower than slamming the items in there manually.

Mohamed Nabawy wrote:
i use background worker but this hang my form and my app is run slowly can i use threading and how

i want solutin plz

Threading doesn't make it quicker. You'd load the list async from the DB, but databinding still has to be done on the mainthread. Binding 55000 items to a ComboBox, just to let the user select one, is a bit overkill. Things would really speed up if you convert it to a readonly textbox with a "set"-button. Open a new form (modal), and then load those 55k items. In a virtualized datagridview, if performance is an issue.

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Nabawoka29-Dec-12 23:53

29-Dec-12 23:53

Eddy Vluggen thanks Smile | :)

OriginalGriff29-Dec-12 4:08

OriginalGriff

29-Dec-12 4:08

To add to what Eddy said - it's a very silly idea to put that many items into a control of any sort if you expect the user to have to pick one of them himself.
Think about it as a user: how are you going to find the one item you want out of 55,000? How much time are you going to waste looking?

Find a better solution! Search, filter, whatever - but not "here's a big list - you sort it out".

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Nabawoka29-Dec-12 23:56

29-Dec-12 23:56

thank OriginalGriff

SledgeHammer0129-Dec-12 8:02

SledgeHammer01

29-Dec-12 8:02

As others have said 55,000 items in a combobox is a HORRIBLE idea. How is anybody going to find an item in there? Find a better design.

Nabawoka29-Dec-12 23:56

Authentication using HTTPWebRequest

29-Dec-12 23:56

HORRIBLE idea Cry | :((

thanks SledgeHammer01

logicon29-Dec-12 1:14

logicon

29-Dec-12 1:14

Hello Everyone,

I am trying to access a page which is secure behind a login system. I do have credentials, but I am trying to automate this as I have to download this page every month.

When I try to use HTTPWebRequest, it doesn't works. I tried to investigate this using Fiddler as well, and here is the log:

Protocol  Host                                   URL
HTTP     TUNNEL to                    subdomain-x.site.com/needed-page.html  <- My request
HTTP     TUNNEL to                    subdomain-y.site.com
:
.
HTTPS    subdomain-y.site.com some-url

What I am trying is:

1. Create Web Request
2. Create Cookie Container
3. Create Network Credentials
4. Create Headers
5. Get Response

However, this returns the Login Page itself. Any help will be highly appreciable.

Re: Authentication using HTTPWebRequest

SledgeHammer0129-Dec-12 9:31

SledgeHammer01

29-Dec-12 9:31

Impossible to say with the info you've given. You need to analyze the login page source code to see how the credentials are sent back to the server and how the actual page you want to access is authenticated. If its just a random SSL page, you just need to fill in the HTTPWebRequest.Credentials object.

Save and Retrieve Image

nirmalgopalakrishnan28-Dec-12 22:02

28-Dec-12 22:02

Hi All,

Could you please assist me in saving and retrieve images to MySQL database using an Image Path.

Let me know, if you require any additional information to assist me.

Thank you,
Nirmal

Richard MacCutchan28-Dec-12 23:18

28-Dec-12 23:18

You need to explain what assistance you need. If you want to save the actual image, then save it as a byte stream or blob (whatever is the MySQL equivalent). If you want to save the file's location then it is just a character string.

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nirmalgopalakrishnan29-Dec-12 5:15

29-Dec-12 5:15

Thank you for your response.

I am saving the image as LongBlob. But retrieving an image through search function, i get parameter not valid error.

byte[] bytesofphotosretrive;
bytesofphotosretrive = (byte[])r["photo"];
MemoryStream mst = new MemoryStream(bytesofphotosretrive);
{
frm1.pictureBox5.Image = Image.FromStream(mst);
}

Please assist.

Regards,
Nirmal

Richard MacCutchan29-Dec-12 5:57

29-Dec-12 5:57

nirmalgopalakrishnan wrote:
i get parameter not valid error.

Where?

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nirmalgopalakrishnan29-Dec-12 6:07

29-Dec-12 6:07

byte[] bytesofphotosretrive;
bytesofphotosretrive = (byte[])r["photo"];
MemoryStream mst = new MemoryStream(bytesofphotosretrive);
{
frm1.pictureBox5.Image = Image.FromStream(mst);
}

the error points to this parameter : frm1.pictureBox5.Image = Image.FromStream(mst);

Richard MacCutchan29-Dec-12 6:17

29-Dec-12 6:17

Well it should not be too difficult to guess which parameter is in error. Use your debugger to step through the code and see exactly what is happening.

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nirmalgopalakrishnan29-Dec-12 19:14

29-Dec-12 19:14

It's pointing to the error in line 164, which is as below:

frm1.pictureBox5.Image = Image.FromStream(mst);

The exception message is: "System.Argument.Exception: Parameter is not valid. at System.Drawing.Image.FromStream(Stream stream, Boolean useEmbeddedColorManagement, Boolean validateImageData) at System.Drawing.Image.FromStream(Stream stream)at btnResearch_Click(Object sender, EventArgs e) in D:\Mat\frmRecSearch.cs: line 164.

Richard MacCutchan29-Dec-12 21:22

29-Dec-12 21:22

Well we already know that. Have you used the debugger to try and determine why the parameter is invalid?

One of these days I'm going to think of a really clever signature.

nirmalgopalakrishnan30-Dec-12 19:57

30-Dec-12 19:57

Could you please email me. nirmalkumarg3@gmail.com

Richard MacCutchan30-Dec-12 22:19

30-Dec-12 22:19

Sorry no, if you have issues to discuss around this problem then post them in this forum; that is why we use it.

One of these days I'm going to think of a really clever signature.

nirmalgopalakrishnan31-Dec-12 17:28