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  • When should I be cautious using data binding in .NET?

    - by Ben McCormack
    I just started working on a small team of .NET programmers about a month ago and recently got in a discussion with our team lead regarding why we don't use databinding at all in our code. Every time we work with a data grid, we iterate through a data table and populate the grid row by row; the code usually looks something like this: Dim dt as DataTable = FuncLib.GetData("spGetTheData ...") Dim i As Integer For i = 0 To dt.Rows.Length - 1 '(not sure why we do not use a for each here)' gridRow = grid.Rows.Add() gridRow(constantProductID).Value = dt("ProductID").Value gridRow(constantProductDesc).Value = dt("ProductDescription").Value Next '(I am probably missing something in the code, but that is basically it)' Our team lead was saying that he got burned using data binding when working with Sheridan Grid controls, VB6, and ADO recordsets back in the nineties. He's not sure what the exact problem was, but he remembers that binding didn't work as expected and caused him some major problems. Since then, they haven't trusted data binding and load the data for all their controls by hand. The reason the conversation even came up was because I found data binding to be very simple and really liked separating the data presentation (in this case, the data grid) from the in-memory data source (in this case, the data table). "Loading" the data row by row into the grid seemed to break this distinction. I also observed that with the advent of XAML in WPF and Silverlight, data-binding seems like a must-have in order to be able to cleanly wire up a designer's XAML code with your data. When should I be cautious of using data-binding in .NET?

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  • drag to pan on an UserControl

    - by Matías
    Hello, I'm trying to build my own "PictureBox like" control adding some functionalities. For example, I want to be able to pan over a big image by simply clicking and dragging with the mouse. The problem seems to be on my OnMouseMove method. If I use the following code I get the drag speed and precision I want, but of course, when I release the mouse button and try to drag again the image is restored to its original position. using System.Drawing; using System.Windows.Forms; namespace Testing { public partial class ScrollablePictureBox : UserControl { private Image image; private bool centerImage; public Image Image { get { return image; } set { image = value; Invalidate(); } } public bool CenterImage { get { return centerImage; } set { centerImage = value; Invalidate(); } } public ScrollablePictureBox() { InitializeComponent(); SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.OptimizedDoubleBuffer, true); Image = null; AutoScroll = true; AutoScrollMinSize = new Size(0, 0); } private Point clickPosition; private Point scrollPosition; protected override void OnMouseDown(MouseEventArgs e) { base.OnMouseDown(e); clickPosition.X = e.X; clickPosition.Y = e.Y; } protected override void OnMouseMove(MouseEventArgs e) { base.OnMouseMove(e); if (e.Button == MouseButtons.Left) { scrollPosition.X = clickPosition.X - e.X; scrollPosition.Y = clickPosition.Y - e.Y; AutoScrollPosition = scrollPosition; } } protected override void OnPaint(PaintEventArgs e) { base.OnPaint(e); e.Graphics.FillRectangle(new Pen(BackColor).Brush, 0, 0, e.ClipRectangle.Width, e.ClipRectangle.Height); if (Image == null) return; int centeredX = AutoScrollPosition.X; int centeredY = AutoScrollPosition.Y; if (CenterImage) { //Something not relevant } AutoScrollMinSize = new Size(Image.Width, Image.Height); e.Graphics.DrawImage(Image, new RectangleF(centeredX, centeredY, Image.Width, Image.Height)); } } } But if I modify my OnMouseMove method to look like this: protected override void OnMouseMove(MouseEventArgs e) { base.OnMouseMove(e); if (e.Button == MouseButtons.Left) { scrollPosition.X += clickPosition.X - e.X; scrollPosition.Y += clickPosition.Y - e.Y; AutoScrollPosition = scrollPosition; } } ... you will see that the dragging is not smooth as before, and sometimes behaves weird (like with lag or something). What am I doing wrong? I've also tried removing all "base" calls on a desperate movement to solve this issue, haha, but again, it didn't work. Thanks for your time.

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  • After drawing circles on C# form how can i know on what circle i clicked?

    - by SorinA.
    I have to represent graphically an oriented graph like in the image below. i have a C# form, when i click with the mouse on it i have to draw a node. If i click somewhere on the form where is not already a node drawn it means i cliked with the intetion of drawing a node, if it is a node there i must select it and memorize it. On the next mouse click if i touch a place where there is not already a node drawn it means like before that i want to draw a new node, if it is a node where i clicked i need to draw the line from the first memorized node to the selected one and add road cost details. i know how to draw the circles that represent the nodes of the graph when i click on the form. i'm using the following code: namespace RepGraficaAUnuiGraf { public partial class Form1 : Form { Graphics graphDrawingArea; Bitmap bmpDrawingArea; Graphics graph; public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { bmpDrawingArea = new Bitmap(Width, Height); graphDrawingArea = Graphics.FromImage(bmpDrawingArea); graph = Graphics.FromHwnd(this.Handle); } private void Form1_Click(object sender, EventArgs e) { DrawCentralCircle(((MouseEventArgs)e).X, ((MouseEventArgs)e).Y, 15); graph.DrawImage(bmpDrawingArea, 0, 0); } void DrawCentralCircle(int CenterX, int CenterY, int Radius) { int start = CenterX - Radius; int end = CenterY - Radius; int diam = Radius * 2; bmpDrawingArea = new Bitmap(Width, Height); graphDrawingArea = Graphics.FromImage(bmpDrawingArea); graphDrawingArea.DrawEllipse(new Pen(Color.Blue), start, end, diam, diam); graphDrawingArea.DrawString("1", new Font("Tahoma", 13), Brushes.Black, new PointF(CenterX - 8, CenterY - 10)); } } } My question is how can i find out if at the coordinates (x,y) on my form i drew a node and which one is it? I thought of representing the nodes as buttons, having a tag or something similar as the node number(which in drawing should be 1 for Santa Barbara, 2 for Barstow etc.)

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  • Automatically resize TableLayoutPanel

    - by Armagan
    I have a programmatically created TableLayoutPanel. It works fine but I couldn't find something: how can I make it size columns automatically when the form is resized? The panel is set to Dock.Top and when I resize the form instead of sizing every column as percents, only last column grows. What can I do for this? Here's how I add ColumnStyle for each column: this.tablePanelFilter.ColumnStyles.Add( new ColumnStyle(SizeType.Percent,Convert.ToSingle( Math.Ceiling((decimal)100 / (decimal)columnCount))));

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  • Fill Combo-box via DataSource Using Values from Various Columns

    - by peace
    Employee emp = new Employee(); comHandledBySQt.DataSource = emp.GetDataFromTable("1"); comHandledBySQt.DisplayMember = "FirstName"; The above code displays drop list of employees first names in a combo box. I want first name and last name to be displayed. How can i do it? I tried to include two columns FirstName and LastName as below but didn't work. comHandledBySQt.DisplayMember = "FirstName" + " " + "LastName"; Any help will be appreciated.

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  • Of Datagridviews, databinding, and non validating cell values.

    - by Yanko Hernández Alvarez
    Lets simplify. Lets say I have this class: class T { public string Name { get; set; } public int Age { get; set; } public int height{ get; set; } ... } and I have a DataGridView's DataSource bound to a BindingList <T>, with N columns, each one bound to each property. I need to: Allow the user to enter non validating ages, heights, etc (for instance "aaa") Color the cells with non validating values (red background) Retain the non validating values displayed until the form is closed (I don't want to lose the values entered until the form is closed, so the user has the option to correct the bad cells anytime he wants BEFORE closing the form) Keep the last correct values entered for each cell with non validating values entered. When the form is closed, ditch the non validating values and keep the last correct values entered. Is there any easy way to do this?

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  • Form.GetChildsAtPoint

    - by serhio
    I would like to obtain the list of controls under a given point. There is a method on System.Windows.Form to obtain a control under a point(GetChildAtPoint) but not point(GetChildsAtPoint). Is there something similar for the list of controls (if borders intersect one other): I need this because I select the objects when user clicks on the panel(I use Microsoft.VisualBasic.PowerPacks.RectangleShape as label bellow). In case if labels are superposed, user should be asked what object to select.

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  • Is it possible to avoid Focus on SplitContainer?

    - by Filini
    The WinForm SplitContainer gets the focus when it's dragged or clicked, while the Splitter does not. The side-effect of this, is that dragging a SplitContainer bar fires Leave/Validate on other controls, and I need to avoid this. I already tried setting TabStop and CausesValidation to False, but with no success. Is there a way to stop the SplitContainer from getting focused? (not a big deal, I can still use the old Splitter, but I lose some nice VS properties...)

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  • Is there a way to get different sizes of the Windows system icons in .NET?

    - by Andrew Watt
    In particular I'd like to be able to get the small (16 x 16) icons at runtime. I tried this: new Icon(SystemIcons.Error, SystemInformation.SmallIconSize) Which supposedly "attempts to find a version of the icon that matches the requested size", but it's still giving me a 32 x 32 icon. I also tried: Size iconSize = SystemInformation.SmallIconSize; Bitmap bitmap = new Bitmap(iconSize.Width, iconSize.Height); using (Graphics g = Graphics.FromImage(bitmap)) { g.DrawIcon(SystemIcons.Error, new Rectangle(Point.Empty, iconSize)); } But that just scales the 32 x 32 icon down into an ugly 16 x 16. I've considered just pulling icons out of the VS Image Library, but I really want them to vary dynamically with the OS (XP icons on XP, Vista icons on Vista, etc.). I'm willing to P/Invoke if that's what it takes.

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  • Change color of text within a RichTextBox in C#

    - by Addie
    I have a RichTextBox that I write a string to every time I click a Form button. The string ends with a newline so each time I add a string, it appends to the bottom of the RichTextBox. Each string begins with the string "Long" or "Short" and ends with Environment.NewLine. I'd like to color each line red if it beings with "Long" and blue if it begins with "Short". How can I do this? If you need further clarification of the question comment below.

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  • Simple regex question (C#, MS SQL)

    - by Vytas999
    Hello, I have some Regex, it looks like this: string regexForDrop = @"^((%27)|'|(\-\-))\s*(d|%64|%44)(r|%72|%52)(o|%6F|%4F)(p|%70|%50)$"; It works fine, when i write to the input "--drop", but it does not works, when i write "drop table users" or something like that. I need that it would be working, no matter what comes after "--drop". How i can implement that? Thanks

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  • Flowlayout panel and autosizing child controls doesn't work

    - by Pete
    I am trying to get a very simple autosizing layout on a winform (C# .NET). I've tried TableLayoutPanels and FlowLayoutPanels but nothing works. I have a usercontrol which is a container for other usercontrols which are created at runtime - I've called it StackPanel as I want it to list the child controls vertically. I've tried this using a FlowLayoutPanel, TableLayoutPanel and a Panel (with each control docked to the top). The child usercontrol consists of a label and then any number of radiobuttons (or any other standard control - it doesn't matter). When the child controls are created, the label text is set (if this is long it needs to wrap to a new line) and the radio buttons are added. There seems to be no combination of docking/autosizing or manual size setting using the Resize events that can get everything to show without clipping and still resize with the form. Thanks!

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  • Using Application Settings and reading defaults from app.config

    - by Peter Goras
    Hi, I need to deploy a Windows Forms application using ClickOnce deployment. (VS2008, .NET 3.5) And I need to provide a configuration file for this app that any user can modify. For this reason, I am using Application Settings instead of standard appSetttings in app.config so I can separate the the user config from app config. see http://msdn.microsoft.com/en-us/library/ms228995(VS.80).aspx Creating a Settings.settings file using VS generated a class with hard-coded default values like this: [global::System.Configuration.DefaultSettingValueAttribute("blahblah")] public string MyProperty ... WTF? I want to read the default values from the app.config! So I created my own class deriving from ApplicationSettingsBase but I cannot get this to read values from the app.config. Any ideas?

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  • How to report DataContext.SubmitChanges() progress with LINQ2SQL

    - by kzen
    If there is a foreach loop that contains DataContext.Customer.InsertOnSubmit(cust) for example: foreach (Object obj in collection) { Customer cust = new Customer { Id = obj.Id, Name = obj.Name ... }; DataContext.Customer.InsertOnSubmit(cust); } And outside of the loop there is a call to: DataContext.SubmittChanges(); Is there a way to obtain the SubmittChanges progress in order to report the progress back to the user (or a different approach without moving the SubmittChanges into the loop)?

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  • How do I pass a reference type to Control.Invoke / display a form centered on the main form

    - by Rubio
    I'm on a thread other than the UI thread and need to display a modal form that's centered on the application's main form. What I usually do is use the width and height of the main form and the modal form to calculate the location, then use the PointToScreen method of the main form to get the location of the modal form. Since I'm on another thread I need to use Control.Invoke to call this method. I just can't figure out how to pass a parameter of type Point to Control.Invoke (params object[]). Value types and String works fine. Or, if someone can find a better way to display a form centered on the main form regardless of thread, that would be great. MessageBox seems to be able to do this (although not modally).

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  • .NET: How to know when serialization is completed?

    - by Ian Boyd
    When I construct my control (which inherits DataGrid), I add specific rows and columns. This works great at design time. Unfortunately, at runtime I add my rows and columns in the same constructor, but then the DataGrid is serialized (after the constructor runs) adding more rows and columns. After serialization is complete, I need to clear everything and re-initialize the rows and columns. Is there a protected method that I can override to know when the control is done serializing? Of course, I'd prefer to not have to do the work in the constructor, throw it away, and do it again after (potential) serialization. Is there a preferred event that is the equivalent of "set yourself up now", so that it is called once whether I'm serialized or not? The serialization i speak of comes from the InitializeComponent() method in the form's code-behind file. #region Windows Form Designer generated code /// <summary> /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// </summary> private void InitializeComponent() { ... } It would have been perfect if InitializeComponent was a virtual method defined by Control, then i could just override it and then perform my processing after i call base: protected override void InitializeComponent() { base.InitializeComponent(); InitializeMe(); } But it's not an ancestor method, it's declared only in the code-behind file. i notice that InitializeComponent calls SuspendLayout and ResumeLayout on various Controls. i thought it could override ResumeLayout, and perform my initialization then: public override void ResumeLayout() { base.ResumeLayout(); InitializeMe(); } But ResumeLayout is not virtual, so that's out. Anymore ideas? i can't be the first person to create a custom control.

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  • How do I Data-Bind dual DateTimePicker to a single DateTime object

    - by S.C. Madsen
    Hi, I have a simple form, with two DateTimePicker-controls: One for date, and one for time. The thing is these two controls are supposed to represent a single point in time. Hence I would like to "Bind" them to a single DateTime property on my form (for simplicity). I did the following: // Start is a DateTime property on the form _StartDate.DataBindings.Add("Value", this, "Start"); _StartTime.DataBindings.Add("Value", this, "Start"); But hooking into "ValueChanged" event, yields mixed results... Sometimes I get exactly what I want, sometimes the updates of the property are "sluggish". I figured this way of splitting into two DateTimePicker's was fairly common. So how to do it? Update: There is possibly multiple questions in there: How do I bind a DateTimePicker (Format: Date) to a DateTime Property on a form? Then, how do I bind yet another DateTimePicker (Format: Time) to the same property? I'm using Visual Studio Express 2008 (.NET 3.5), and I seemingly get ValueChanged events from the DateTimePickers before the value is changed?

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  • Handle ConstraintException and get ColumnName that cause the error

    - by Mysterious
    Hello, I have a Table Machines that made of: ID = Identity , Primary , AutoIncrement,NOT NULL SN = Unique , String , NOT NULL Name =String now I am using a form to insert data into this table, and I am using BindingSource and ErrorProvider, I am handling Null and Empty string in the DataSet layer (partial class in the dataset.xsd), now when I try to end editing this.machinesBindingSource.EndEdit(); I got this error message: ex.Message = "Column 'SN' is constrained to be unique. Value '123' is already present." I know I entered a duplicated value but the question is HOW can I determine which the columnName that cause the error and re-write the error message entirely in different language I want to get the columnName and the wrong value thanks in advance

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  • C# Button Text Unicode characters.

    - by Fossaw
    C# doesn't want to put Unicode characters on buttons. If I put \u2129 in the Text attribute of the button, the button displays the \u2129, not the Unicode character, (example - I chose 2129 because I could see it in the font currently active on the machine). I saw this question before, link text, but the question isn't really answered, just got around. I am working on applications which are going all over the world, and don't want to install all the fonts, more then "don't want", there are that many that I doubt the machine I am working on has sufficient disk space. Our overseas sales agents supply the Unicode character "numbers". Is there another way forward with this? As an aside, (curiosity), why does it not work?

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  • Accessing non-static combbox property in the static method.

    - by Harikrishna
    I have one combobox on the window form and I have one method which is declared with static like private static DataTable ParseTable(HtmlNode table) Now I want to use combobox in that method for using combobox property but I can not access any property of combobox or combobox itself.If I made the combobox declaration as static then it can be accessed in that static method.But any alternative way to access combbox property in that static method because I don't want to make combobox declaration as static.

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  • Change the style of WinForm border?

    - by Dodi300
    Is it possible to change the style of a WinForm border? I know that if the border is removed, it takes away the functionality to resize the program. Therefore is there a way to change the style of it? At the moment, I've removed the text from the border, set the "FormBorderStyle" to "SizableToolWindow" and set the "ControlBox" to false. That makes it look like this: But I want it to look something like this, but still be resizeable: (Maybe with a different color line)

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