The Manning formula for open-channel flow is: whereV= Velocityn = Manning’s “n”,r = Hydraulic radius = area / wetted perimeter = b*y / (2*y + b) for a rectangular channel (where y = depth and b = width), ands = slope of channel (m/m). Discharge Q = V*A = V*b*y. We cannot solve this…
Windows stores program settings in the Registry, a Windows internal database. You can use this to remember previous user choices and use them as defaults the next time. We typically remember window positions, file paths, and other settings with the Registry. These three commands work with items stored in the Registry: SaveSetting appname, section, key,…
1. The Application Keyword Use “Application” to refer to Excel, e.g.: Application.ActivePrinter Name of the Active Printer.Application.Name Name of the program running (“Microsoft Excel”).Application.Path The path from which the program is running. 2. ActiveControl Instead of the name of a specific control (e.g. txtEdit), you can use the keyword ActiveControl. This will let your program refer…
While you can pick these Shortcut Keys up from the menus in the Excel Visual Basic Editor, it is useful to have them all in one place. F1 Help on the highlighted itemF2 Object BrowserShift+F2 View Definition (Go to highlighted Sub or Function)F3 Repeat last FindF4 Display Properties WindowF5 Run / Continue RunF8 Single Step…
You can use Excel Visual Basic to read and write text files (Sequential and Random file access). But we will not touch on text files in this post. Rather, we will look at how to save and open Excel files using Excel code, plus a few valuable functions: The bigger examples below are in the…
The built-in dialog boxes, MsgBox and InputBox$, are very useful for getting input from the user. But sooner or later you will want to go further. You might, while running code, want the user to make a choice from a list, or between several options. For this, you want a UserForm. For example: The program…
In an earlier post, we looked at connecting VBA code to command buttons on the Worksheet, the Quick Access Toolbar and the Ribbon. What about the other ActiveX Controls: The Combo Box, List Box, or Check Box? How about Option Buttons, the Scroll Bar, Spin button, Toggle button, etc.? That’s coming up in this post….
In our previous post, we looked at connecting VBA code to command buttons on the Worksheet, the Quick Access Toolbar and the Ribbon. What about the other Form Controls: The Combo Box, List Box, or Check Box? How about Option Buttons, the Scroll Bar, the Spin button, the Label, etc.? That’s coming up in this…
1. What are Controls? First, some terminology. If you wanted to run a macro from a worksheet, you could create a button on the worksheet for the user to click. Such a button is a Control. There are many types of controls, which we will use in a later post. Apart from Command Buttons to…
1. What are Objects and Collections? Visual Basic defines a number of what it calls Objects. Examples of Objects are: In object-orientated terminology, Objects belong to Classes. Collections are groups of Objects. Here are some examples of Collections that Visual Basic defines: 2. The Excel Object Model Excel, too, has objects of its own. When…
Before Excel 2003, you could get a complete list of Visual Basic Functions by looking in Visual Basic Help > Contents > Functions. In Excel 2010, entering “Functions” into the Help Search box produces nothing useful. Using a specific category, e.g. “Math Functions”, may be more productive. Please be aware of what references to “Excel…
It is difficult to make your program foolproof, because fools are so ingenious! Even so, one should make an effort to trap and handle errors. You should not let the program simply crash if there is a problem, whether due to bad data, faulty calculation, or whatever. This is what we call Error-Handling. Excel Visual…