EditLabel UserControl

EditLabel is editable Label control, who's text can be modified at run-time by double-clicking on it. Under the hood, it contains a Label control and TextBox control. It works like a Label control until you double-click it with the mouse. When double-clicked it enters 'edit-mode' where a TextBox overlays the Label. The control will AutoSize to the characters you type in the TextBox, updating the Label's size at the same time. You can leave the control's edit mode by hitting either enter, the escape key, or letting the control lose focus. After editing, the control acts like a label again, with the updated text. You can check out the code for the EditLabel project here on my GitHub.

The EditLabel isn't too interesting by itself, but I wanted to blog about it for all the interesting attributes that I never knew about until I started getting into designing controls, and controlling how controls are displayed in the designer window in visual studio.

The first thing my EditLabel control needed was and event that the parent form could subscribe to know when the text changed. Creating the event simply isn't enough. If you want the event to show up in the Visual Studio's Form Designer when you click on events, you need to add the Browsable and EditorBrowsable attribute. This will make is show up in the designer. You can control the description that appears as well as what category it shows up under when viewing events/properties in the Categorize view as opposed to Alphabetical view by using the Description and Category attributes respectively:

[Category("Property Changed")]
[Description("Event raised when the value of the Text property is changed on Control.")]
[Browsable(true), EditorBrowsable(EditorBrowsableState.Always)]
public new event EventHandler TextChanged;

There is also the notion of default events. That is, the event for which a handler is added when you double click the control in the designer. For example, when you double click a TextBox, it automatically adds the TextChanged event, instead of, say, the KeyDown event. To make an event the default event, add the DefaultEvent attribute at the control's class-level declaration:

[DefaultEvent("TextChanged")]
public partial class EditLabel : UserControl
{
   ...

Another thing I wanted was the Text property. Like a Label or a TextBox control, I wanted a public Text property that could be edited at design time. However, every time I re-built the project, the text would get reset to the default. As it turns out, if you want modifications to properties to be persisted, it must be serialized to the MainForm.Designer.cs, or whatever the auto-generated Designer.cs file is. In order to tell the designer to serialize changes made at design time to Designer.cs file, you have to add the DesignerSerializationVisibility attribute above the property. Here is the attributes and declaration for the Text property:

[Category("Appearance")]
[Description("The text associated with the control.")]
[Browsable(true), EditorBrowsable(EditorBrowsableState.Always)]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
public override string Text
{
   get { return ctrlLabel.Text; }
   set { ChangeText(value); }
}

You can view the full EditLabel.cs here, or view the entire EditLabel project here.

Resize form to match the contents of DataGridView

Sometimes the sole purpose of a Form is to display a DataGridView. In that case, you probably want the Form to automatically resize to the size of the contents in the DataGridView. I've seen solutions that loop through all the rows and add up the height, but this is ugly, and usually does not take into account margins, padding, DividerHeight and row header padding. There must be a better way...

My strategy is to temporarily undock the DataGridView, set AutoSize to true, then capture the DataGridView's Size at that point, then restore the Dock and AutoSize property. Then use the captured size to resize the Winform:

// Within the Form class
private void AutoSizeFormToDataGridView()
{
 Size contentsSize = GetDataGridViewContentsSize();
 this.ClientSize = contentsSize;
}

protected Size GetDataGridViewContentsSize()
{
 DockStyle dockStyleSave = dataGridView1.Dock;
 dataGridView1.Dock = DockStyle.None;
 dataGridView1.AutoSize = true;
 
 Size dataContentsSize = dataGridView1.Size;
 
 dataGridView1.AutoSize = false;
 dataGridView1.Dock = dockStyleSave;
 return dataContentsSize;
}

Or alternatively you can define this as an extension method:

public static Size GetContentsSize(this DataGridView dataGrid) { //...

Enjoy!

DataTable or DataGridView to CSV or HTML file using Clipboard

It turns out that DataGridView.GetClipboardContent() returns all the selected cells of a DataGridView as a type DataObject, which is conveniently consumed by the Windows.Forms.Clipboard class, as well as other WYSIWYG editors from Microsoft. From this you can set the Clipboard, then get the clipboard various data formats, including:
- Comma separated value
- Tab separated value
- HTML

So instead of looping though columns and then rows, you can output the entire DataGridView as a CSV file in just 3 lines of code! (4 if you count setting the ClipboardCopyMode, which can be set in the Form Builder.

Here is the code:

void DataGridViewToCSV(string Filename)
{
   bool allowAddRows = dataGridView1.AllowUserToAddRows;
   bool rowHeadersVisible = dataGridView1.RowHeadersVisible;
   dataGridView1.AllowUserToAddRows = false;
   dataGridView1.RowHeadersVisible = false;

   // Choose whether to write header. You will want to do this for a CSV file.
   dataGridView1.ClipboardCopyMode = DataGridViewClipboardCopyMode.EnableAlwaysIncludeHeaderText;
   // Select the cells we want to serialize.
   dataGridView1.SelectAll(); // One could also use DataGridView.Rows[RowIndex].Selected = true;

   // Save the current state of the clipboard so we can restore it after we are done
   IDataObject objectSave = Clipboard.GetDataObject();
   // Copy (set clipboard)
   Clipboard.SetDataObject(dataGridView1.GetClipboardContent());
   // Paste (get the clipboard and serialize it to a file)
   File.WriteAllText(Filename,Clipboard.GetText(TextDataFormat.CommaSeparatedValue));
   // Restore the current state of the clipboard so the effect is seamless
   if(objectSave != null)
   {
      Clipboard.SetDataObject(objectSave);
   }
   dataGridView1.AllowUserToAddRows = allowAddRows;
   dataGridView1.RowHeadersVisible = rowHeadersVisible;
}

Some improvements

For a tab-delimited file, use the TextDataFormat.Text enum in your call to Clipboard.GetText(). You can also output your DataGridView as HTML by using TextDataFormat.Html instead of TextDataFormat.CommaSeparatedValue, but there is extra header data you have to parse out:

   string result = Clipboard.GetText(TextDataFormat.CommaSeparatedValue);
   result = result.Substring( result.IndexOf("") );

Notes:
- An object must be serializable for it to be put on the Clipboard.