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This just a sample.

Actually i use one static dataset in my application and can display in two diffrent windows forms (suppose parent and child) same data table in the same time, all work fine, till i start to fill this data table in one form, in this case Fill operation are maked very slow. But when i use so one form and fill data table exatamente in it all work fine. Example above just describe this situation.

There could be two reasons. Either the statement used for fill is slow or the existing binding is making it slow. Before filling the dataset, remove any bindings to it and rebind after the fill. Perhaps that would help.

The need to optimize rises from a bad design.

My articles[^]

Yes its a solution. But why when i fill this table in the same form where binded my control (either without rebinding) all work fine, but when in another all work very slow????? Thats the Point.

modified on Monday, October 27, 2008 3:52 AM

As I said in the first post, the scenarios are not the same.

In your first example you fill the dataset. So it seems that you don't have a datatable in the dataset, but it's created during fill.

In the second example, you already have a datatable and you're filling it. So it makes me wonder if you have existing event handlers, binding etc. attached to the datatable. If so, they can be the cause to the slow fill. Especially if binding is involved since existing binded objects must be refreshed when binding is done. This wouldn't be the case in example 1.

Without seeing the actual situation, it's merely guessing. However, the filling speed should be equal in both cases if the query is the same and the 'surroundings' are the same (eventhandlers etc)

The need to optimize rises from a bad design.

My articles[^]

Hello everyone,

I am designing an application which could be treated as a framework application to host other components, e.g. functions like component life cycle management and delegate from client to call the components.

Now I have two design patterns, and I want to ask for advice about which one is better and why.

Design pattern 1, using interface, for example, let client application impement interface, which contains method called Initialization, and my application framework call Initialization method when I want to initialize a component;

Design pattern 2: using event for example, OnIntialize event, client application register event handler (callback), and when my application framework wants to initialize a component, I will send OnInitialize event.

Any advice?

thanks in advance,
George

I like design pattern 1 based on the Kiss principle.

Need software developed? Offering C# development all over the United States, ERL GLOBAL, Inc is the only call you will have to make.

Happiness in intelligent people is the rarest thing I know. -- Ernest Hemingway

Most of this sig is for Google, not ego.

Besides this, are there any technical reasons why you prefer option 1?

regards,
George

George_George wrote:
I am designing an application which could be treated as a framework application to host other components

Get real. Based on your collection of threads here in CodeProject that is a task well, Well, WELL beyond your current understanding of software development fundamentals. Dead | X|

led mike

led mike wrote:
Get real.

That's every bot's dilemma, isn't it?

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Damn near pulled muscle laughing at that one!

led mike

Do you have any advice or comments to my original question? Smile | :)

regards,
George

I do not quite understand what do you mean "Get real"? Could you say some other words please? Smile | :)

regards,
George

Whatever dude. Disagree with me all you want, you have a far better grasp of the subject than I do. Roll eyes | :rolleyes:

led mike

Hi led mike,

Could you provide some technical advice or comments please? Smile | :)

have a good weekend,
George

Hi alll,
How to scroll a listview with out scroll bar. I know

ListBox1.EnsureVisible(index)

will do the job, but since i have disabled Scrollable property using

ListBox1.Scrollable = false

EnsureVisible is not doing the job.

is there any other way to scroll listview with scrollable propery set to false

Regards
Vayanans

I don't think of any idea in c# windows application. But if you could explain your scenario a bit, perhaps i could be able to give you any suggestion.

Ahsan Ullah
Senior Software Engineer

hi I dont want to use scroll bar to scroll the listview. i have two buttons for scrolling u and down
is there is any way to do so...?

Regards
Vayanans

you should make a user control like listview by using textboxes for example. Then put your own buttons for moving it up or down.

Ahsan Ullah
Senior Software Engineer

..and why not resort to setting the scrollable for a second?

bool oldVal = ListBox1.Scrollable;
ListBox1.Scrollable = true;
ListBox1.EnsureVisible(index);
ListBox1.Scrollable = oldVal;

Put the list box on a panel. Make the list box tall enough to display all the items at the same time. Make you buttons move the list box up and down so what ever part of the panel you want visible can be seen in the panel.

Here's a sample of what I mean using a label. Just create a new winforms app, and paste this over the form1 definition:

public partial class Form1 : Form
{
    private System.Windows.Forms.Panel panel1;
    private System.Windows.Forms.Label label1;
    private System.Windows.Forms.Button button1;
    private System.Windows.Forms.Button button2;

    public Form1()
    {
        InitializeComponent();

        // Create the controls.
        this.panel1 = new System.Windows.Forms.Panel();
        this.button1 = new System.Windows.Forms.Button();
        this.button2 = new System.Windows.Forms.Button();
        this.label1 = new System.Windows.Forms.Label();

        //
        // panel1
        //
        this.panel1.Controls.Add(this.label1);
        this.panel1.Location = new System.Drawing.Point(93, 12);
        this.panel1.Size = new System.Drawing.Size(60, 50);
        this.panel1.TabIndex = 0;
        //
        // button1
        //
        this.button1.Location = new System.Drawing.Point(12, 12);
        this.button1.Size = new System.Drawing.Size(75, 23);
        this.button1.TabIndex = 0;
        this.button1.Text = "Up";
        this.button1.UseVisualStyleBackColor = true;
        this.button1.Click += new System.EventHandler(this.scrollUp);
        //
        // button2
        //
        this.button2.Location = new System.Drawing.Point(12, 41);
        this.button2.Size = new System.Drawing.Size(75, 23);
        this.button2.TabIndex = 0;
        this.button2.Text = "Down";
        this.button2.UseVisualStyleBackColor = true;
        this.button2.Click += new System.EventHandler(this.scrollDown);
        //
        // label1
        //
        this.label1.Location = new System.Drawing.Point(0, 0);
        this.label1.Name = "label1";
        this.label1.Size = new System.Drawing.Size(60, 186);
        this.label1.TabIndex = 1;
        this.label1.Text = "This is a label with some text that goes on for ages and ages to " +
            "demonstrate how it is possible to manually scroll a control using a panel.";


        // Add the controls to the form.
        this.Controls.Add(this.button2);
        this.Controls.Add(this.button1);
        this.Controls.Add(this.panel1);

        this.ClientSize = new System.Drawing.Size(169, 75);
    }

    private void scrollUp(object sender, EventArgs e)
    {
        label1.Top += 10;
        if (label1.Top > 0)
        {
            label1.Top = 0;
        }
    }

    private void scrollDown(object sender, EventArgs e)
    {
        label1.Top -= 10;
        if (label1.Top < panel1.Height-label1.Height)
        {
            label1.Top = panel1.Height - label1.Height;
        }
    }
}

imon

BeginReceive is used in my class for receiving data over TCP/IP.
When reaching the callback of BeginReceive, the class fires an event and puts the received data in the EventArgs.

I use the class in a Form that displays received data. But I can't show the data without Invoke.

Does anyone know how to fire the Event without the necessity of Invoke outside the class?

class1 (receives TCP/IP data)
{
  public event EventHandlerDataReceived DataReceived;
  private byte[] recPacket = new byte[32000];

  private void WaitForData()
  {
    // Async receiving
    sockClient.BeginReceive(recPacket, 0, recPacket.Length, SocketFlags.None, new AsyncCallback(OnDataReceived), null);
  }

  private void OnDataReceived(IAsyncResult asyn)
  { 
    // Async callback 
    sockClient.EndReceive(asyn)
    OnDataReceived(this, new DataReveivedEventArgs(recPacket)
  }

  public void OnDataReceived(object sender, DataReveivedEventArgs e)
  {
    // Fire event that carries reveived Data in EventArgs
    if (DataReceived != null) { DataReceived(this, e); }
  }

class2 (Form)
{
  class1 tcpClass = new class1();
  
  public class2()
  {
    // Initialisation of event 
    tcpClass.DataReceived += new tcpClass.EventHandlerDataReceived(tcpClass_DataReceived);
  }

  private void tcpClass_DataReceived(object sender, DataReveivedEventArgs e)
  {
    // Problem: Can't get off from the thread BeginReceive
    // Invoke would be necessary. That makes usage of class1 very uncomfortable.

    txtData.Text = e.Data.ToString();
  }
}

No, you have to use Invoke.

GUI controls can only be accessed from the GUI thread. Here you are trying to access it from another thread.

A nice readable way to do this would be have a separate method to perform the update.

public void UpdateTextBox(String data)
{
    if (this.InvokeRequired)
    {
        this.Invoke(new Action<string>(UpdateTextBox), data);
        return;
    }

    txtData.Text = data;
}

This is a pretty standard pattern.

Simon

Isn't it possible to place an Invoke in the function that fires the event?

In a Form can be used InvokeRequired and BeginInvoke.
But in my TCP class I can't find any possibility for Invoke.

Kurt wrote:
Isn't it possible to place an Invoke in the function that fires the event?

Not really because the class that is firing the event doesn't know what thread it should be invoking on.

The form is a GUI control, so it knows what thread the GUI thread is.

The class that is creating the event shouldn't be forced to raise the event on the GUI thread, that would be bad design, sometimes you might not want it on the GUI thread, particularly if you are doing things in the background.

It is the form that should be responsible for transferring the control to the GUI thread when updating controls.

Simon

First: Thank you for yor help!

Hmm, I thought of making a DLL, so the users can double click the event in the property window and fill in individual code. But the user would be forced to use invoke.

We can use so many different controls in our projects and use their events without invoke. Do all those controls doesn't use asynchronous processes?