VB Graph: Use XPosData to Plot Fractional X-Axis Values

ID Number: Q85264

1.00

WINDOWS

Summary:

You can use the Graph custom control (GRAPH.VBX) XPosData property to

give independent X-axis values for graphs. That is, the graph is not

forced to plot on the X-axis, and has the ability to plot fractional

data points between X-axis values. This property can be used with all

graphs types except pie.

This information applies to the Graph custom control supplied with

Microsoft Professional Toolkit for Microsoft Visual Basic programming

system version 1.0 for Windows.

More Information:

By default, graphs use a dependent X-axis scale. This means data

points plotted conform to the whole-number increments shown on the X-

axis. To plot fractional X-axis values, use the XPosData property.

The XPosData values are set for each data point, allowing fractional

X-axis plotted values to appear in the graph. XPosData sets the X

coordinate, and GraphData sets the Y coordinate. The example below

demonstrates this by plotting three different data points on a scatter

graph:

Example

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1. Run Visual Basic, or from the File menu, choose New Project (ALT,

F, N) if Visual Basic is already running. Form1 is created by

default.

2. From the File menu, choose Add File. In the Files box, select the

GRAPH.VBX custom control file. The GRAPH tool appears in the

Toolbox.

3. Place a Graph (Graph1) on Form1 by double-clicking the Graph tool

in the Toolbox.

4. In the Properties box, set the following properties for Graph1:

- AutoInc = 0 (Off)

- GraphType = 9 (Scatter)

- NumPoints = 3

- SymbolData = 3 (Solid triangle - up)

5. Add the following code to Form1:

Sub Form_Load ()

Graph1.ThisPoint = 1 'This indicates which datapoint to work on

Graph1.GraphData = 10 'This sets the Y-axis value for this point

Graph1.XPosData = .2 'This sets the X-axis value for this point

Graph1.ThisPoint = 2

Graph1.GraphData = 5

Graph1.XPosData = 1.3

Graph1.ThisPoint = 3

Graph1.GraphData = 3

Graph1.XPosData = 2.4

End Sub

6. Press F5 to run the code.

This example, when run, plots three data points in (X,Y) format. In

this case, XPosData is used to provide non-integer X-axis values. The

three triangles are plotted using the following coordinates:

(.2, 10), (1.3, 5), (2.4, 3)

XPosData works for other graph types too, except pie, for which X-axis

data has no meaning. To try this example with another graph type,

change the GraphType property of Grid1 to "4 - 3D Bar". Notice how the

bars orient against the X-axis when you run the code.

Additional reference words: 1.00