Label in Windows Forms Diagram

A label is a text object that is attached to a node and is positioned relative to node coordinates. This enables you to format the label text. You can also customize the appearance of the label. You can bind the node name to the label so that the name will be displayed as the label text. This can be achieved using the PropertyBinding property.

The following formatting options are supports for the label text:

  • WrapText
  • HorizontalAlignment
  • VerticalAlignment
  • DirectionRightToLeft
  • DirectionVertical
  • TextCase
  • NoClip
  • LineLimit
  • FitBlackBox
  • MeasureTrailingSpace

The following options are supports for customizing the appearance of the label.

  • BackGroundStyle
  • FontColorStyle
  • FontStyle

Use Case Scenarios

When you are drawing a Business Process Flow Diagram, using this support, you can name the node representing the stage.

Tables for Properties and Methods

Property Description Type Data Type Reference links
Name Used to specify the name of a label. NA string NA
FullName Used to specify the full name of a label. Label container’s name is prefixed with its name. NA string NA
ReadOnly Used to add a flag indicating whether the text object is Read-only or not. NA Boolean NA
Visible Specifies the visibility of the label. NA Boolean NA
FontColorStyle Specifies the font color style. NA FillStyle NA
BackgroundStyle Specifies the text background style. NA FillStyle NA
Text Gets or sets the label text. NA String NA
FontStyle Specifies the font style. NA FontStyle NA
PropertyBinding Binds the text value of the label to the Text property. NA LabelPropertyBinding NA
Size Gets or sets the label text size. NA SizeF NA
SizeToNode Set the node size to label size. This can be enabled if the node has only one label and label's position is center. NA Boolean NA
UpdatePosition Gets or Sets whether default positioning has to be used. NA Boolean NA
AdjustRotationAngle Gets or Sets whether the label should remain horizontal on rotation of the node. NA Boolean NA
TextCase Gets or sets the case of the text in the label. NA TextCases NA
HorizontalAlignment Gets or sets the horizontal alignment of the text. NA StringAlignment NA
VerticalAlignment Gets or sets the vertical alignment of the text. NA StringAlignment NA
FormatFlags Gets the flags used to format the text. NA StringFormatFlags NA
WrapText Gets or sets a value indicating whether text should be wrapped, when it exceeds the width of the bounding box. NA Boolean NA
DirectionRightToLeft Gets or sets a value indicating whether the text is right to left. NA Boolean NA
DirectionVertical Gets or sets a value indicating whether the text is vertical. NA Boolean NA
FitBlackBox Gets or sets a value indicating whether no part of any glyph overhangs the label bounds. NA Boolean NA
LineLimit Gets or sets a value indicating whether only entire lines are laid out in the formatting rectangle. NA Boolean NA
MeasureTrailingSpaces Gets or sets a value indicating whether space at the end of each line in calculations that measure the size of the text. NA Boolean NA
NoClip Gets or sets a value indicating whether overhanging parts of glyphs and unwrapped text reaching outside the formatting rectangle are allowed to show. NA Boolean NA
OffsetX Gets or sets the label offset x in percent relative to node's width from node's top left point. NA float NA
OffsetY Gets or sets the label offset y in percent relative to node's width from node's top left point. NA float NA
Position Gets or sets the position of the label. NA Position NA
Constraints Gets or sets a constraints to define an interact the label. enum LabelConstraints NA
RotationAngle Gets or sets the rotation angle for the label. NA float NA

Methods

Method Description Parameters Type Return Type Reference links
GetPosition Gets the label position in the node coordinates. Empty NA PointF NA
GetStringFormat Creates a StringFormat object that encapsulates the properties of the text object. Empty NA StringFormat NA

Adding a Label to an Application

You can create label as illustrated in the following code example:

RoundRect node = new RoundRect(0, 0, 170, 100,MeasureUnits.Pixel);

//Create a label with predefined position
Syncfusion.Windows.Forms.Diagram.Label lbl_TopCenter = new Syncfusion.Windows.Forms.Diagram.Label(node, "Label_TopCenter");           

//Position the label
lbl_TopCenter.Position = Position.TopCenter;

/* Position enum has the values Center, TopLeft, TopCenter, TopRight, MiddleLeft, MiddleRight, BottomLeft, BottomCenter, BottomRight and Custom */

//Apply font style
lbl_TopCenter.FontStyle.Bold = true;
lbl_TopCenter.FontStyle.Family = "Corbel";
lbl_TopCenter.FontStyle.Size = 9;

//Add the label to node's label collection
node.Labels.Add(lbl_TopCenter);

//Create a label with custom position
Syncfusion.Windows.Forms.Diagram.Label lbl_Custom = new Syncfusion.Windows.Forms.Diagram.Label(node, "Label_Custom");

//Position the label
lbl_Custom.Position = Position.Custom;
lbl_Custom.OffsetX = 0;
lbl_Custom.OffsetY = 0;

//Apply font style
lbl_Custom.FontStyle.Bold = true;
lbl_Custom.FontStyle.Family = "Corbel";
lbl_Custom.FontStyle.Size = 9;

//Format the label text
lbl_Custom.HorizontalAlignment = StringAlignment.Center;
lbl_Custom.VerticalAlignment = StringAlignment.Far;

//WrapText is set to true by default

//Add the label to node's label collection
node.Labels.Add(lbl_Custom);

//Add the node to diagram model
diagram1.Model.AppendChild(node);
Dim node As New RoundRect(0, 0, 170, 100,MeasureUnits.Pixel)

'Create a label with predefined position
Dim lbl_TopCenter As New Syncfusion.Windows.Forms.Diagram.Label(node, "Label_TopCenter")

'Position the label
lbl_TopCenter.Position = Position.TopCenter

' Position enum has the values Center, TopLeft, TopCenter, TopRight, MiddleLeft, MiddleRight, BottomLeft, BottomCenter, BottomRight and Custom
'Apply font style
lbl_TopCenter.FontStyle.Bold = True
lbl_TopCenter.FontStyle.Family = "Corbel"
lbl_TopCenter.FontStyle.Size = 9
 
'Add the label to node's label collection
node.Labels.Add(lbl_TopCenter)

'Create a label with custom position
Dim lbl_Custom As New Syncfusion.Windows.Forms.Diagram.Label(node, "Label_Custom")

'Position the label
lbl_Custom.Position = Position.Custom
lbl_Custom.OffsetX = 0
lbl_Custom.OffsetY = 0

'Apply font style
lbl_Custom.FontStyle.Bold = True
lbl_Custom.FontStyle.Family = "Corbel"
lbl_Custom.FontStyle.Size = 9

'Format the label text
lbl_Custom.HorizontalAlignment = StringAlignment.Center
lbl_Custom.VerticalAlignment = StringAlignment.Far

'WrapText is true by default
'Add the label to node's label collection
node.Labels.Add(lbl_Custom)

'Add the node to diagram model
diagram1.Model.AppendChild(node)

Adding a Label

Label Orientation

This feature lets the user to specify the orientation of a node label. There are two orientation modes, Horizontal, which displays the label horizontally, and Auto, which rotates the label based on the node or connector rotation angle.

Property Description Data Type
Orientation Gets or sets the orientation of the label. Enum

The following code shows how to set the orientation of the label to horizontal:

Syncfusion.Windows.Forms.Diagram.Label label = new Syncfusion.Windows.Forms.Diagram.Label(node, "Orientation");

//Sets the orientation of the label as horizontal.
label.Orientation = LabelOrientation.Horizontal;
node.Labels.Add(label);
Dim label As New Syncfusion.Windows.Forms.Diagram.Label(node, "Orientation")

'Sets the orientation of the label as horizontal.
label.Orientation = LabelOrientation.Horizontal
node.Labels.Add(label)

Label Orientation

Label-Orientation

Interaction

Diagram allows label to be interacted by selecting, dragging, rotating, and resizing. By default, the Label interaction is disabled and you can enable this by using the Constraints property of the Label. You can also curtail the services of interaction by enabling either selecting, dragging, rotating, or resizing individually with the respective Constraints property of the label. The following code illustrates how to enable annotation interaction.

Syncfusion.Windows.Forms.Diagram.Rectangle rectangle = new Syncfusion.Windows.Forms.Diagram.Rectangle(new RectangleF(100, 100, 100, 100));

Syncfusion.Windows.Forms.Diagram.Label label = new Syncfusion.Windows.Forms.Diagram.Label();
//To set the label constraint as Interaction...
label.Constraints = LabelConstraints.Interaction;
label.Text = "Welcome to Syncfusion";
rectangle.Labels.Add(label);

label = new Syncfusion.Windows.Forms.Diagram.Label();
//To set the label constraint as Resize alone...
label.Constraints = LabelConstraints.Resize | LabelConstraints.Select;
label.Position = Position.TopLeft;
//lbl.UpdatePosition = true;
label.Text = "Second";
label.ReadOnly = true;
rectangle.Labels.Add(label);

label = new Syncfusion.Windows.Forms.Diagram.Label();
//To set the label constraint as Rotate alone...
label.Constraints = LabelConstraints.Rotate| LabelConstraints.Select;
label.Position = Position.MiddleRight;
label.Text = "Third";
rectangle.Labels.Add(label);
diagram1.Model.AppendChild(rectangle);
Dim rectangle As New Syncfusion.Windows.Forms.Diagram.Rectangle(New RectangleF(100, 100, 100, 100))

Dim label As New Syncfusion.Windows.Forms.Diagram.Label()
'To set the label constraint as Interaction...
label.Constraints = LabelConstraints.Interaction
label.Text = "Welcome to Syncfusion"
rectangle.Labels.Add(label)

label = New Syncfusion.Windows.Forms.Diagram.Label()
'To set the label constraint as Resize alone...
label.Constraints = LabelConstraints.Resize| LabelConstraints.Select
label.Position = Position.TopLeft
'lbl.UpdatePosition = true;
label.Text = "Second"
label.ReadOnly = True
rectangle.Labels.Add(label)

label = New Syncfusion.Windows.Forms.Diagram.Label()
'To set the label constraint as Rotate alone...
label.Constraints = LabelConstraints.Rotate| LabelConstraints.Select
label.Position = Position.MiddleRight
label.Text = "Third"
rectangle.Labels.Add(label)

diagram1.Model.AppendChild(rectangle)