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Heath thanks
It still didn't solve my problem, actually it causes more. I understand your points, but i'm still learning and as a result my coding is getting complicated.
I tried your solution but it appears that rather than stopping my flickering, when I have a mousedown event (in ucappts) i now get two seperate imagaes and when I move it around both images wipe out the background image and when the mouseup event fires does not repaint like it did before it. how do get the OnPaint event in ucmain to fire when I'm in ucappts?
thnaks for your insight and help
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bobrad wrote:
my coding is getting complicated
Welcome to the world of development. 
The solution I presented to you is the correct way of doing this. When you have rather complex graphics you should use double-buffering (that's debatable, but most would agree) so that you don't tie up the control thread.
When you're moving your control, form, whatever, or minimizing it or even passing your mouse over it (in Windows 2000 and newer, the mouse part isn't exactly true thanks to layered windows) everything in the invalidated ("affected") area is repainted. Efficient drawing routines only repaint what they have to (the invalidated region - not the entire client area). So, your form's OnPaint is already being called. And actually, that's not what even paints the form or most of the other controls in the BCL (base class library). Most controls merely encapsulate the Windows Common Controls (the same controls you see in most other applications and in Windows itself - they're native) and the Window APIs. Native code paints them using the WM_PAINT message, which in turn invokes the OnPaint method (from within WndProc - the window procedure encapsulated in managed code), which in turn fires the Paint event for a control.
The problem you're witnessing is something else. As I mentioned in my first reply, however, once you enable to those ControlStyles to get double-buffering, you're responsible for painting the background as well (the SystemColors class defines static properties to get you these colors).
As to why you're seeing two images, I'm not sure quite what you mean. Perhaps you could post a screenshot somewhere and paste the link here (you can take screenshots using the PrtScn keyboard button, or use Alt+PrtScn to take a screenshot of just the active window; then paste it into some graphics program or even Microsoft Paint (mspaint.exe) and save it).
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Software Design Engineer
Developer Division Sustained Engineering
Microsoft
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I understand what you are saying but I'm unsure as how to implement what you are saying; Im unsure how to repaint a the background which is in the parent user control (ucmain) when I'm in the child (user control ucappts)
I tried using a delegae to redraw the background, it works somwhat
I tried to post the code here for the two usercontrols but it's too much and looks really ugly. is there a better place to post my code?
thanks for all you help
bob
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You don't need to paint the parent control - that's what I've been trying to say. It gets automatically repainted when anything affects any part of its client area. If that client area includes your control then your control gets the WM_PAINT message (translates to the OnPaint method, which fires the Paint event - which you should handle in your derivative control since it's slower and you have less control) and you should repaint only the area (the PaintEventArgs.ClipRectangle, although with more complex graphics that can be difficult).
If you want examples of owner-drawn controls, just search here at CodeProject. There are dozens - if not hundreds - of examples of just about every type of control you can think of (and good and bad articles, so watch the article rating near the top...and longer articles are usually a sign of more detailed articles that you should take a look at).
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Sustained Engineering
Microsoft
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hi, i've this datagrid. each time i click the row header of the datagrid, i wanna put the value of col1 into a variable. the value in the variable will change everytime i click on different row header. is like using currencymanager to bind the datagrid onto textbox,but instead i wanna bind it into a variable.
Chris
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You don't need data binding for this, nor do I suggest it. If all you're doing is storing the row index (which you shouldn't do; the CurrencyManager manages that) or some value in the one of the row's column, data binding is completely unnecessary.
All you need to do is handle the DataGrid.RowHeaderClick event, get the current mouse position (in screen coordinates) using the static Control.MousePosition property, convert that to client coordinates in reference to the DataGrid (DataGrid.PointToClient), then pass that to DataGrid.HitTest. That will get you the row index. Using this approach, however, has it's problems. Unless you're binding against a DataView that tracks the sorting and filtering instead, you may have difficulting resolving the right row in the DataSet with the right row in the DataGrid (the row indexes will be out of sync) when the user sorts the data or filters it (if allowed). The method below mitigates this problem.
You could avoid all this, however, knowing that when you click a row it becomes the current row. You then get the current row from the CurrencyManager like so:
CurrencyManager cm = (CurrencyManager)
dataGrid1.BindingContext[dataGrid1.DataSource, dataGrid1.DataMember];
if (cm != null)
{
DataRowView rowView = cm.Current as DataRowView;
if (rowView != null)
myVariable = rowView[0].ToString();
}
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Software Design Engineer
Developer Division Sustained Engineering
Microsoft
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hi, im able to store it into the variable but only the first row. the value is not changing when i select other row on the datagrid.
Chris
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What does your (relevent) code look like? Just telling me that it doesn't work doesn't help diagnose the problem, but if you post snippets of your code that would help.
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Software Design Engineer
Developer Division Sustained Engineering
Microsoft
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sorry, here is my coding. thanks
SQL = "SELECT * FROM TABLE ORDER";
cmd = new System.Data.OleDb.OleDbCommand (SQL, conn);
adapter = new System.Data.OleDb.OleDbDataAdapter(cmd);
ds = new System.Data.DataSet();
adapter.Fill(ds,"TABLE");
dataGrid1.DataSource = ds;
dataGrid1.DataMember ="TABLE";
CurrencyManager cm = (CurrencyManager)dataGrid1.BindingContext[dataGrid1.DataSource,dataGrid1.DataMember];
string myVariable;
if (cm != null)
{
DataRowView rowView = cm.Current as DataRowView;
if (rowView != null)
{
myVariable = rowView["startDate"].ToString();
}
}
Chris
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sorry there was some typo error..
SQL = "SELECT * FROM TABLE";//<-- without "Order"
cmd = new System.Data.OleDb.OleDbCommand (SQL, conn);
adapter = new System.Data.OleDb.OleDbDataAdapter(cmd);
ds = new System.Data.DataSet();
adapter.Fill(ds,"TABLE");
dataGrid1.DataSource = ds;
dataGrid1.DataMember ="TABLE";
CurrencyManager cm = (CurrencyManager)dataGrid1.BindingContext[dataGrid1.DataSource,dataGrid1.DataMember];
string myVariable;
if (cm != null)
{
DataRowView rowView = cm.Current as DataRowView;
if (rowView != null)
{
myVariable = rowView["startDate"].ToString();
}
}
Chris
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I'm not sure if you're posting just snippets from various methods or if this is your entire method. If the latter is true, then of course it won't work. You need to declare myVariable (and I certainly hope you haven't given it that non-descript name) as a field (so you don't loose it after setting it) and put everything below that in your code snippet in an event handler for DataGrid.RowHeaderClick (which means you'll have to extend DataGrid with your own control since RowHeaderClick is protected), or just handle the Click event, like so:
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Data.Common;
using System.Data.SqlClient;
public class Form1 : Form
{
private DataGrid dataGrid1;
private Label label1;
private SqlCommand sqlSelectCommand1;
private SqlConnection sqlConnection1;
private SqlDataAdapter sqlDataAdapter1;
private DataView dataView1;
public Form1()
{
InitializeComponent();
}
protected override void OnLoad(EventArgs e)
{
DataSet ds = new DataSet();
sqlDataAdapter1.Fill(ds);
dataView1 = new DataView(ds.Tables[0]);
dataView1.AllowDelete = false;
dataView1.AllowEdit = false;
dataView1.AllowNew = false;
dataGrid1.DataSource = dataView1;
}
private void InitializeComponent()
{
this.dataGrid1 = new DataGrid();
this.label1 = new Label();
this.sqlSelectCommand1 = new SqlCommand();
this.sqlConnection1 = new SqlConnection();
this.sqlDataAdapter1 = new SqlDataAdapter();
((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).BeginInit();
this.SuspendLayout();
this.dataGrid1.Anchor = ((AnchorStyles)((((AnchorStyles.Top | AnchorStyles.Bottom)
| AnchorStyles.Left)
| AnchorStyles.Right)));
this.dataGrid1.DataMember = "";
this.dataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText;
this.dataGrid1.Location = new System.Drawing.Point(8, 8);
this.dataGrid1.Name = "dataGrid1";
this.dataGrid1.Size = new System.Drawing.Size(280, 208);
this.dataGrid1.TabIndex = 0;
this.dataGrid1.Click += new System.EventHandler(this.dataGrid1_Click);
this.label1.Anchor = ((AnchorStyles)(((AnchorStyles.Bottom | AnchorStyles.Left)
| AnchorStyles.Right)));
this.label1.Location = new System.Drawing.Point(8, 224);
this.label1.Name = "label1";
this.label1.Size = new System.Drawing.Size(280, 23);
this.label1.TabIndex = 1;
this.sqlSelectCommand1.CommandText = "SELECT ProductID, ProductName, SupplierID, CategoryID, QuantityPerUnit, UnitPrice" +
", UnitsInStock, UnitsOnOrder, ReorderLevel, Discontinued, CategoryName FROM [Alp" +
"habetical list of products]";
this.sqlSelectCommand1.Connection = this.sqlConnection1;
this.sqlConnection1.ConnectionString = "workstation id=ALICE;packet size=4096;integrated security=SSPI;data source=\".\";pe" +
"rsist security info=False;initial catalog=Northwind";
this.sqlDataAdapter1.SelectCommand = this.sqlSelectCommand1;
this.sqlDataAdapter1.TableMappings.AddRange(new DataTableMapping[] {
new DataTableMapping("Table", "Alphabetical list of products", new DataColumnMapping[] {
new DataColumnMapping("ProductID", "ProductID"),
new DataColumnMapping("ProductName", "ProductName"),
new DataColumnMapping("SupplierID", "SupplierID"),
new DataColumnMapping("CategoryID", "CategoryID"),
new DataColumnMapping("QuantityPerUnit", "QuantityPerUnit"),
new DataColumnMapping("UnitPrice", "UnitPrice"),
new DataColumnMapping("UnitsInStock", "UnitsInStock"),
new DataColumnMapping("UnitsOnOrder", "UnitsOnOrder"),
new DataColumnMapping("ReorderLevel", "ReorderLevel"),
new DataColumnMapping("Discontinued", "Discontinued"),
new DataColumnMapping("CategoryName", "CategoryName")})});
this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
this.ClientSize = new System.Drawing.Size(296, 253);
this.Controls.Add(this.label1);
this.Controls.Add(this.dataGrid1);
this.Name = "Form1";
this.Text = "Form1";
((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).EndInit();
this.ResumeLayout(false);
}
static void Main()
{
Application.Run(new Form1());
}
private void dataGrid1_Click(object sender, EventArgs e)
{
CurrencyManager cm = (CurrencyManager)dataGrid1.BindingContext[
dataGrid1.DataSource, dataGrid1.DataMember];
if (cm != null)
{
DataRowView view = cm.Current as DataRowView;
if (view != null)
label1.Text = view[1].ToString();
}
}
}
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles] [My Blog]
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I'm trying to control FlashGet using COM in my .NET application. I made a wrapper class of the jccatch COM server. I create an instance of the JetCarNetscapeClass defined in the wrapper class. The method AddUrl works fine - it has three string parameters. The problem comes from the AddUrlList method. In the original declaration in the COM server it has a VARIANT* pList parameter, and the wrapper class marshalizes it as ref object pList. So, when I pass an array or ArrayList of strings, an exception is thrown. What kind of parameter should I pass to the method or how can I change the default marshalizing behavior? I couldn't find a solution and I searched a lot.
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And ArrayList will not marshal the same as an array of strings. What you passed to the interop'd method AddUrlList depends on what the documentation states.
More than likely you must pass it a SAFEARRAY. Since you created an interop assembly (RCW) using VS.NET or tlbimp.exe, you've lost the opportunity to define the correct UnmanagedType to the MarshalAsAttribute, namely the UnmanagedType.SafeArray type. You can, however, re-declare the same interface yourself with the ComImportAttribute and the correct GuidAttribute and ComInterfaceAttribute (with values the same as the one in the interop assembly). If you read the documentation for the UnmanagedType.SafeArray you should get some idea of how to marshal the string[] array correctly.
You could also try using Marshal.GetNativeVariantForObject, but you'll need additional methods from the Marshal class to marshal the returned IntPtr correctly as an object. The method above would probably be easier (you won't have to marshal the data yourself; .NET will do it for you).
Again, though, this all depends on what the AddUrlList is expecting. If you were to tell us what the API documentation states (not what tlbimp.exe or VS.NET thinks it should be in the interop assembly), that will most likely help.
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles] [My Blog]
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Hi,
I'm trying to add a context menu to my form that would contain only items that can be checked. I would like the context menu to stay open when the user clicks an item. This way, they wouldn't need to re-open the context menu to check 5 or 6 items at once.
So basically, open the context menu, check a few items, then click out of the context menu to close it.
Is it possible? I thought about reopening the menu after every click but that seems like a stupid solution (and the flickering is ugly).
Thanks!
Carl
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Using the MenuItem and derivative classes defined in the .NET BCL, no. These encapsulates the native menu APIs in a basic manner.
You'll either need to figure out an alternative UI (like a popup (modal) dialog to check the options, which are still reflected upon by the menus (so they share data)) or use a third-party library (or develop your own menu'ing systme).
In .NET 2.0, the menus and toolbars as you know them are dead. Well, not dead (you can still use them) but superceeded by Winbars which look and act very much like Office menus and toolbars, so you can site about any control you want on them, including a simple borderless dialog that doesn't go away until dismiss (you have control over what happens). These are not constrained by the current menu APIs.
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles] [My Blog]
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Heath,
Thanks for your answer. That sounds like a lot of work for the benefits (since the users would have used this feature only once in a while).
Thanks again!
Carl
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Carl,
I don't think what Heath is suggesting would take alot of work. Just do this:
1) Hook into the MouseClick event and see if the right mouse has been clicked.
2) Create a simple form with the checkboxes and make it a non-sizable dialog.
3) The user checks to their hearts content then clicks the OKAY button
4) You process the results. Voila, you replace the context menu with what you need!!!
There are 10 kinds of people in the world.
Those that read binary...
...and those who don't.
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That may seem like a stupid solution, but it may be the only one you have. You are trying to change the nature of a context menu (or any menu for that matter). You either need to create your own control from scratch or you could just create a small dialog box with checkboxes instead. Just create a selection in your current context menu that says "Set Options", and then open a dialog box with your checkboxes in it when that option is selected. I know this isn't the answer you're looking for, but I can't think of any way to override context menu behaviour without some inelegant hack that, from a useability perspective, probably shouldn't be done anyhow.
Best Regards.
-Matt
------------------------------------------
The 3 great virtues of a programmer:
Laziness, Impatience, and Hubris.
--Larry Wall
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I’ve got a problem. That is, when we use those Windows APIs,such as SetupDiGetClassDevs() and SetupDiEnumDeviceInterfaces(),
to enumerate all the instances of the usb device class, what I wanna make sure are the answers to these questions:Is there a certain
rule which determines the order of being enumerated among all the instances? In other words,If we can depend on a certain rule to
foreknow which device instance will be enumerated first,which will be the next and which will be the last? If there is,then what
it is? If not,how can we let the first attached one be first enumerated,the next will be next,and the last will be last?
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Your question has absolutely nothing to do with C#. You need to either read the documentation for the functions you're P/Invoking (in the Platform SDK at http://msdn.microsoft.com/library[^]) or pack the returned data into an array in C# and sort it using Array.Sort and an IComparer implementation (like Comparer.Default which works for the intrinsics and strings).
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles] [My Blog]
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Hi...
I want my Application to run when windows start..!
I didn't know how to do it, so i searched the registry on my computer and found the key i think was the right ("HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run")
I tried to do this...
string path = Environment.CurrentDirectory + "\\MyApp.exe";
RegistryKey App = Registry.LocalMachine;
RegistryKey App = App.OpenSubKey("HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run\\");
App.SetValue("MyApp", path);
But that did not work.... it throws a "'System.NullReferenceException' -
Additional information: Object reference not set to an instance of an object."
Then I tried this....
string path = Environment.CurrentDirectory + "\\MyApp.exe";
Registry.LocalMachine.OpenSubKey("Software").OpenSubKey("Microsoft").OpenSubKey("Windows").OpenSubKey("CurrentVersion").OpenSubKey("Run").SetValue("MyApp", path);
But it also thorws an error -> "'System.UnauthorizedAccessException' occurred in mscorlib.dll - Additional information: Cannot write to the registry key."
I have no idea what to do then!
Can anyone help me how to write to the registry or tell me a way so my application will run when windows start?
Thanks...!
QzRz
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Put a shortcut in the startup folder of the start menu.
Christian
I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer
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I dont understand what you mean...
is there a folder i can put a shortcut in so it automaticly will run it when windows start..?
if that is what you mean.... how can i find it...? (need to find it also if it is not on same drive on every computer)
QzRz
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Click 'Start', go up to 'Programs', and expand the list if necessary. There's a folder there called 'Startup'. An install program should allow you to put a shortcut there, or alternatively, the folder structure is stored at <current user documents and settings location>\Start Menu\Programs\Startup. There are functions that help you find the location of special folders like the one windows is in, or the one where your documents and settings live.
Christian
I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer
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LOL. How can someone not know about this??? 
Alex Korchemniy
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