StatusBarPanel objects for our application

In this section we will add the new panels to our status bar, and define some text for the first two panels. The final panel is an owner-drawn panel, and is the subject of section 4.4.

4.3.1Adding panels to a status bar

Let’s begin by adding our three panels to the status bar. In Visual Studio, panels are not added via the Toolbox, but rather through the Panels item in the Property window. If you are not using Visual Studio, you can create StatusBarPanel objects like you would any other object for your form.

Set the version number of the application to 4.3.

ADD STATUS BAR PANELS

1In the designer window, display the Properties window for the statusBar1 control.

ADD STATUS BAR PANELS (continued)

ADD STATUS BAR PANELS (continued)

5 Add the third panel (panel 2).

Settings

As is our custom, let’s look at an excerpt of the code generated by these actions.

private System.Windows.Forms.StatusBarPanel sbpnlImagePercent; private System.Windows.Forms.StatusBarPanel sbpnlImageSize; private System.Windows.Forms.StatusBarPanel sbpnlFileName;

. . .

private void InitializeComponent()

{

. . .

this.sbpnlFileName = new System.Windows.Forms.StatusBarPanel(); this.sbpnlImageSize = new System.Windows.Forms.StatusBarPanel(); this.sbpnlImagePercent = new System.Windows.Forms.StatusBarPanel(); ((System.ComponentModel.ISupportInitialize)

(this.sbpnlFileName)).BeginInit(); ((System.ComponentModel.ISupportInitialize) =

(this.sbpnlImageSize)).BeginInit(); ((System.ComponentModel.ISupportInitialize)

(this.sbpnlImagePercent)).BeginInit();

System.Windows.Forms.StatusBarPanelAutoSize.Spring;

this.sbpnlFileName.BorderStyle =

System.Windows.Forms.StatusBarPanelBorderStyle.None;

this.sbpnlFileName.Text = "statusBarPanel1"; this.sbpnlFileName.ToolTipText = "Image File Name"; d Set tool tip text

}

Some of the properties here are a little different than we have seen before. The StatusBarPanel is not a control, but rather a Component object similar to our menu object.

bThe StatusBarPanel object must be fully initialized before it can be used within the StatusBar control. The ISupportInitialize interface specifies that this object uses a simple transacted notification for batch initialization. When creating such an object, use of the BeginInit and EndInit methods supported by this interface should be used to ensure proper initialization.

cSince panels exist within a status bar control, properties exist to indicate how to draw the panel within the containing control. See .NET Table 4.3 for a summary of all properties in the StatusBarPanel class. Some properties used here are briefly explained in the following list.

•AutoSize indicates whether the panel is automatically sized within the status

bar, and if so how. This property uses the StatusBarPanelAutoSize enumeration, with the following values:

•BorderStyle indicates the type of border to use for the panel, taken from the

StatusBarPanelBorderStyle enumeration:

•Style indicates how the panel should be drawn, taken from the StatusBarPanelStyle enumeration:

As you can see from the code, two of our panels display text in the status bar, and one of them is an owner-drawn panel. Each of the AutoSize values are used.

dPanels provide a built-in tool tip mechanism in the ToolTipText property. These appear when the cursor hovers over the corresponding panel. We will look at the ToolTips class in chapter 13 as a way to support tool tips for classes derived from the

Control object.

eFinally, note the changes to our statusBar1 variable. The set of panels is added to the Panels property using the AddRange method.

this.statusBar1.Panels.AddRange(new

System.Windows.Forms.StatusBarPanel[] {

this.sbpnlFileName,

this.sbpnlImageSize,

this.sbpnlImagePercent});