Re: More Efficient Code - C# Discussion Boards

DataGridViewCheckBoxColumn

22-Sep-05 8:09

You could do a simple loop:

string input = "ABCD";
string output = string.Empty;
for (int i = input.Length - 2; i >= 0; i++)
{
  output += input.Substring(i, 2);
}

There's lots of ways you can do this, since it's simple string parsing. The fact that the input string is in hexadecimal is moot if you never need to convert it. Now, if you actually wanted to convert it to numbers you could do something like the following:

string input = "ABCD";
int high = int.Parse(input.Substring(0, 2), NumberStyles.AllowHexSpecifier);
int low = int.Parse(input.Substring(2, 2), NumberStyles.AllowHexSpecifier);

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Drew McGhie22-Sep-05 7:22

Drew McGhie

22-Sep-05 7:22

Here's my issue in a nutshell. I have a table that I bind to columns in a DGV, and, in addition, I have one nonbound DataGridViewCheckBoxColumn in the [0] position. In my code, I bind the data, but upon trying to access the checkboxes, I get errors that say the values are null. How do I check the .Checked property of the checkboxes?

//relevant code, cut/pasted so it might be out of order.
//
// dataGridView1
//
this.dataGridView1.AllowUserToAddRows = false;
this.dataGridView1.AllowUserToDeleteRows = false;
this.dataGridView1.AllowUserToResizeColumns = false;
this.dataGridView1.AllowUserToResizeRows = false;
this.dataGridView1.AutoGenerateColumns = false;
this.dataGridView1.ColumnHeadersHeightSizeMode = System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize;
this.dataGridView1.Columns.AddRange(new System.Windows.Forms.DataGridViewColumn[] {
this.dgvcbcSelect,
this.dgvtbcName,
this.dgvtbcDescription,
this.AttachmentKey,
this.AttachmentType,
this.AttachmentSourceID,
this.AttachmentID,
this.FileName,
this.FileSize,
this.ContentType});
this.dataGridView1.DataSource = this.attachmentBindingSource;
this.dataGridView1.Dock = System.Windows.Forms.DockStyle.Fill;
this.dataGridView1.Location = new System.Drawing.Point(0, 25);
this.dataGridView1.Name = "dataGridView1";
this.dataGridView1.Size = new System.Drawing.Size(792, 241);
this.dataGridView1.TabIndex = 1;
//
// dgvcbcSelect
//
this.dgvcbcSelect.HeaderText = "Select";
this.dgvcbcSelect.Name = "dgvcbcSelect";
this.dgvcbcSelect.Width = 50;
//
// dgvtbcName
//
this.dgvtbcName.DataPropertyName = "Name";
this.dgvtbcName.HeaderText = "Name";
this.dgvtbcName.Name = "dgvtbcName";
this.dgvtbcName.Width = 150;
//
// dgvtbcDescription
//
this.dgvtbcDescription.AutoSizeMode = System.Windows.Forms.DataGridViewAutoSizeColumnMode.Fill;
this.dgvtbcDescription.DataPropertyName = "Description";
this.dgvtbcDescription.HeaderText = "Description";
this.dgvtbcDescription.Name = "dgvtbcDescription";

// ALL OTHER COLUMNS HAVE .visible=false;

Anyways, when I load the form that has the datagrid, I do this:
{
InitializeComponent();
myAttachmentClient = new AttachmentClient(); //holder for the dataset
myAttachmentClient.LoadAttachmentList(inKey); //loads the data from a SQL server
versionKey = inKey;
dataGridView1.DataSource = myAttachmentClient.AttachmentTable;
}

After this, putting in MessageBox.Show(dataGridView1.Rows[0].Cells[0].Value.ToString()); gives me an error. How can I access the 'checked'-ness of the checkboxes?

Re: DataGridViewCheckBoxColumn

Drew McGhie22-Sep-05 7:59

Drew McGhie

22-Sep-05 7:59

Oohh, found my solution. Its MessageBox.Show(dataGridView1.Rows[0].Cells[0].FormattedValue.ToString()). Fuuuuun.

More Efficient Code

Debs*22-Sep-05 6:58

Debs*

22-Sep-05 6:58

The current program I am working on has a lot of user Checkboxs and currently when ever I change a property I end up coding something like this:
CheckBox1->Enabled=true;
CheckBox2->Enabled=true;
...
CheckBox30->Enabled=true;
this is obviously not a very efficient way of doing this... so I'm looking for a more efficient way... maybe something along the lines of

for(int c=0;c!=31;c++)
{
CheckBox(c)->Enabled=true;
}

this code will obviously not work but any suggestions on how to make something like this work??? Unsure | :~

Cheers*
Debs

therealmccoy22-Sep-05 7:03

therealmccoy

22-Sep-05 7:03

If all of your checkboxes are located in a container control (panel, groupbox) or if they are the only controls on your form then you could use a foreach statement.

foreach(Control aControl in form1.controls)
{
CheckBox aCheckBox = (CheckBox) aControl;
aCheckBox.Enabled = true;
}

I did not test the above code. It's just off the top of my head.

You could also create and arraylist of checkboxes and interate through then the same way.

www.lovethosetrains.com

-- modified at 13:10 Thursday 22nd September, 2005

Robert Rohde22-Sep-05 8:06

Robert Rohde

22-Sep-05 8:06

You could put all CheckBoxes into an array and iterate over it:

//instance member
CheckBox[] _allCheckBoxes;

//somewhere once all CheckBoxes are created
_allCheckBoxes = new CheckBox[31];
_allCheckBoxes[0] = CheckBox1;
_allCheckBoxes[1] = CheckBox2;
//...


//then if you have to change all of them
foreach (CheckBox cb in _allCheckBoxes)
cb.Enabled = true;

Niklas Ulvinge22-Sep-05 8:51

Niklas Ulvinge

22-Sep-05 8:51

Are you sure thats possible?
When I try to do it it wont work, it give's me A LOT of errors and all kinds of warnings.

Niklas Ulvinge aka IDK

Robert Rohde22-Sep-05 9:05

Robert Rohde

22-Sep-05 9:05

Well...

yes Im sure Smile | :)

.

If you want I can mail you a small sample.

Debs*22-Sep-05 10:30

Debs*

22-Sep-05 10:30

Thanks for the suggestions I will try them out Big Grin | :-D

Debs

Re: More Efficient Code -SOLVED

Niklas Ulvinge23-Sep-05 0:42

Niklas Ulvinge

23-Sep-05 0:42

Is it possible to do it with menuitems?

And sure, mail the sample to me...
My email is: ulvinge@gmail.com

Niklas Ulvinge aka IDK

Debs*23-Sep-05 7:11

Debs*

23-Sep-05 7:11

Thanks for all the suggestions I managed to do do it by the following: Big Grin | :-D

TCheckBox *ChkBx[34];
ChkBx[0]=CheckBox1; //Declaring them all once into an array
ChkBx[1]=CheckBox2;
...
ChkBx[33]=CheckBox33;

for(int i=0;i!=4;i++)
{
ChkBx[i]->Checked=true;
}

I also used this concept with Graph Line Series ie.
TChartSeries *Ser[4];
...
Thanks Again
Debs

-- modified at 13:11 Friday 23rd September, 2005

IEnumIDList.Next(...) is not working :(

daouner22-Sep-05 5:28

22-Sep-05 5:28

Hello!

Ihave extendended the ShellLib (from arikp's article) to support the IEnumIDList interface. Here is the code:

<br />
        [ComImport]<br />
	[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]<br />
	[Guid("000214F2-0000-0000-C000-000000000046")]<br />
	public interface IEnumIDList<br />
	{<br />
		[PreserveSig]<br />
		Int32 Clone(out IntPtr ppenum);<br />
<br />
		[PreserveSig]<br />
		Int32 Next(UInt32 celt, <br />
			[MarshalAs(UnmanagedType.LPArray, SizeParamIndex=0)]<br />
			out IntPtr[] rgelt,<br />
			out UInt32 pceltFetched<br />
			);<br />
<br />
		[PreserveSig]<br />
		Int32 Reset();<br />
<br />
		[PreserveSig]<br />
		Int32 Skip(UInt32 celt);<br />
	}<br />

and I get an instance of this interface using:

<br />
                public static IEnumIDList GetEnumIDList(IntPtr ptrEnumIDList)<br />
		{<br />
			System.Type shellEnumIDListType =                      System.Type.GetType("ShellLib.IEnumIDList");<br />
			Object obj = Marshal.GetTypedObjectForIUnknown(ptrEnumIDList, shellEnumIDListType);<br />
			IEnumIDList RetVal = (IEnumIDList)obj;<br />
			return RetVal;<br />
		}<br />

If I try this code:

<br />
                        UInt32 celt = 10;<br />
			IntPtr[] ptrList = new IntPtr[celt];<br />
			UInt32 count;<br />
                        EnumIDList.Next(celt, out ptrList, out count)<br />

The Shell dosen't fill the ptrList and count is 0. The IShellFolder is the Desktop folder.

<br />
                IntPtr ptrFoldersList;<br />
		iDesktopFolder.EnumObjects(this.Handle, (Int32)ShellApi.SHCONTF.SHCONTF_FOLDERS | (Int32)ShellApi.SHCONTF.SHCONTF_STORAGE, out ptrFoldersList);<br />

If you need any details please let me know. I don't really see what I did wrong... (maybe I'm dumb Smile | :)

).

Thank you!

Heath Stewart22-Sep-05 6:29

22-Sep-05 6:29

When deriving your interface from IUnknown (which is what happens in the CLR when you specify ComInterfaceType.InterfaceIsIUnknown for the InterfaceTypeAttribute on the interface), the methods must be in the ordered defined - not the order documented. This means the interface should be defined as:

[Guid("000214F2-0000-0000-C000-000000000046"),
 InterfaceType(ComInterfaceType.InterfaceIsIUnknown),
 ComImport]
public interface IEnumIDList
{
  [PreserveSig] int Next(ulong celt, IntPtr[] rgelt, out ulong pceltFetched);
  [PreserveSig] int Skip(ulong celt);
  [PreserveSig] int Reset();
  [PreserveSig] int Clone(out IEnumIDList ppenum);
}

This is also true of ComInterfaceType.InterfaceIsDual. If you use only ComInterfaceType.InterfaceIsIDispatch then you must have attribute your methods and properties with the correct DispIdAttribute values.

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daouner22-Sep-05 7:25

22-Sep-05 7:25

It works now! Thank you very much. I'll keep that in mind next time.

daouner22-Sep-05 10:00

22-Sep-05 10:00

Or not... All I get is the same folder that called EnumObjects. pceltFetched == 1 in all the situations and the rgelt[0] points to the parents PIDL. Very strange... Any explications would be very helpful. Thank you.

Heath Stewart22-Sep-05 11:06

22-Sep-05 11:06

I would have to see more of your implementation to know how you're using it.

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daouner23-Sep-05 7:19

23-Sep-05 7:19

In my test projects this are the functions that manage the IEnumIDList Interface:

<br />
public static IEnumIDList GetEnumIDList(IntPtr ptrEnumIDList)<br />
		{<br />
			System.Type shellEnumIDListType = System.Type.GetType("JSoftware.CustomTools.ShellLib.IEnumIDList");<br />
			Object obj = Marshal.GetTypedObjectForIUnknown(ptrEnumIDList, shellEnumIDListType);<br />
			IEnumIDList RetVal = (IEnumIDList)obj;<br />
			return RetVal;<br />
		}<br />
<br />
		public static String[] GetSubFolders(IEnumIDList EnumIDList)<br />
		{<br />
			UInt32 celt = 10;<br />
			IntPtr[] ptrList = new IntPtr[celt];<br />
			UInt32 count = 5;<br />
<br />
			String[] PathList;<br />
<br />
			IShellFolder iSubFolder;<br />
			IntPtr ptrRelative = IntPtr.Zero;<br />
			IntPtr ptrSubFolder;<br />
			ShellApi.STRRET ptrData;<br />
<br />
			EnumIDList.Reset();<br />
<br />
			if (EnumIDList.Next(celt, ptrList, out count) == 0)<br />
			{<br />
				PathList = new String[count];<br />
				for (UInt32 i = 0; i < count; i++)<br />
				{<br />
					ShellApi.SHBindToParent(ptrList[i], ShellGUIDs.IID_IShellFolder, out ptrSubFolder, ref ptrRelative);<br />
					iSubFolder = GetShellFolder(ptrSubFolder);<br />
					iSubFolder.GetDisplayNameOf(ptrRelative, (uint)ShellApi.SHGNO.SHGDN_NORMAL, out ptrData);<br />
					ShellApi.StrRetToBSTR(ref ptrData, ptrList[i], out PathList[i]);<br />
				}<br />
				return PathList;<br />
			}<br />
			return null;<br />
		}<br />

The code that uses those functions:

<br />
private void GetMainFolders()<br />
{<br />
DummyTreeNode RootNode;<br />
IntPtr ptrRootFolder;<br />
ShellApi.SHGetFolderLocation(this.Handle, (short)ShellApi.CSIDL.CSIDL_DRIVES, IntPtr.Zero, 0, out ptrRootFolder);<br />
IShellFolder iRootFolder= ShellFunctions.GetShellFolder(ptrRootFolder);<br />
				IntPtr ptrFoldersList;<br />
<br />
				ShellApi.STRRET iInfo;<br />
				iRootFolder.EnumObjects(this.Handle, (Int32)ShellApi.SHCONTF.SHCONTF_FOLDERS | (Int32)ShellApi.SHCONTF.SHCONTF_NONFOLDERS, out ptrFoldersList);<br />
IEnumIDList iFoldersList = ShellFunctions.GetEnumIDList(ptrFoldersList);<br />
RootNode = (DummyTreeNode)Nodes[0];<br />
RootNode.AddSubFolders(iFoldersList);<br />
}<br />
<br />
public void AddSubFolders(IEnumIDList EnumIDList)<br />
		{<br />
			try<br />
			{<br />
				String[] SubFolders = ShellFunctions.GetSubFolders(EnumIDList);<br />
				for (int i = 0; i < SubFolders.Length; i++)<br />
				{<br />
					this.Nodes.Add(new DummyTreeNode(SubFolders[i]));<br />
				}<br />
					<br />
			}<br />
			catch (Exception e)<br />
			{<br />
				System.Windows.Forms.MessageBox.Show(e.Message);<br />
			}<br />
		}<br />
<br />

DummyTreeNode is a class that inherits from TreeNode class. Nodes[0] exists and it is the iRootFolder display name. (These are beta functions and are harder to read... sorry for that)

PS: I get an ExecutionEngineException in GetShellFolder(ptrRootFolder)...

Heath Stewart23-Sep-05 7:27

23-Sep-05 7:27

And ExecutionEngineException is hardly a small matter for a "PS" - that's about the worst exception the CLR can throw, which indicates a problem with the CLR itself. I also don't know what GetShellFolder does.

You might consider running a repair on the .NET Framework from the Add/Remove Programs control panel applet.

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Software Design Engineer
Developer Division Customer Product-lifecycle Experience
Microsoft

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daouner23-Sep-05 7:34

23-Sep-05 7:34

<br />
public static IShellFolder GetShellFolder(IntPtr ptrShellFolder)<br />
		{<br />
			System.Type shellFolderType = GetShellFolderType();<br />
			Object obj = Marshal.GetTypedObjectForIUnknown(ptrShellFolder, shellFolderType);<br />
			IShellFolder RetVal = (IShellFolder)obj;<br />
			return RetVal;<br />
		}<br />
<br />
public static Type GetShellFolderType()<br />
		{<br />
			System.Type shellFolderType = System.Type.GetType("JSoftware.CustomTools.ShellLib.IShellFolder");<br />
			return shellFolderType;<br />
		}<br />

It was the first time i used GetShellFolder (until now I used SHGetDesktopFolder because I wanted iRootFolder to be the Desktop folder). Thank you for the support!

daouner23-Sep-05 9:08