For example, while a human's age in years is always a positive value between 0 and 120 (with a few historical or mythical exceptions), if you're working with adults that can fly an airplane, the range is far narrower. These can be considered business criteria, but as often as not, they're simply common-sense rules. Later in this chapter, I illustrate ways to add properties to the TextBox control to validate the datatype and ensure that data provided falls within a specified range.ĭata also needs to be restricted and validated based on a number of other ever-changing criteria, such as minimum and maximum permitted values, precision, scale, and format. This way, if an error occurs, the user can easily change the data to match the criteria. This means that the TextBox, DataGridView, MaskedEdit, ComboBox, or whatever UI control is used to capture input needs to be programmed to accept only valid data. Since user-provided values are usually the source of incorrect data, it's essential that input (or edited) data be validated for datatype, range, business rules, and "reasonableness" while the user is focused on the input control.
Since the TextBox control (a typical source of user input) manages its Text property as a String, the value can be virtually anything, so you'll need some technique to validate the TextBox Text to ensure it conforms to the correct datatype. However, since the Value property is often (usually) reset based on user input or by program logic just before the SqlCommand is executed, it's essential that the supplied input variable datatype match the SqlParameter object's assigned datatype. When a new SqlParameter object is instantiated, the DbType and SqlType are set to the specified value in the constructor and match the datatype of the Value (if it's supplied) or NVarChar if it's not supplied. The challenges we faced and address in this chapter are: $LASTEXITCODE the equivalent to cmd.exe %ERRORLEVEL%, and you can use it as follows in your PowerShell scripts: &dism.Peter and I spent more than a week researching and discussing the best ways to deal with SqlParameter Value validation.
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The PowerShell $LASTEXITCODE should be 0, since $LASTEXITCODE contains the exit code of the last Win32 executable execution. ~~~~~~~~~~~~~ CategoryInfo : NotSpecified: (:), COMExceptionįullyQualifiedErrorId : .GetConfigu $handlers = Get-WebConfiguration /system.webServer/handlers/add -Loca … If( $os_version -ge ( New-Object System.Version "10.0" )) block, you don’t see the PowerShell errors like: Get-WebConfiguration : Filename: \?\z:\sites\Line number: 14Įrror: There is a duplicate '/scripting/scriptResourceHandler' section defined # Always be careful comparing strings and integers!
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# for more information about Windows Server versions. Those commands are easily wrapped into a PowerShell script, and here it is: $os_version = ::OSVersion.Version
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In my Windows Server disk cleanup using DISM blogpost, I’ve shown you how to clean up your Windows Server WinSxs folder with DISM.
To illustrate PowerShell’s $? usage, have a look at the following DISM Cleanup-Image command. The PowerShell operator $? contains True if the last operation succeeded and False otherwise. 2 PowerShell’s $LASTEXITCODE Powershell $? operator
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