Inno Setup - check if a program is installed? (the program is Microsoft Report Viewer Redistributable 2008)

I would like to know how to have the inno setup installer will detect if MS RV 2008 is installed, if it is because nothing happens, and if not installed and open it. exe in the installer (开发者_JAVA百科I already I have this code with ShellExec).

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Use inno setup to detect if registry setting is there.

ie...

"read from registry" constant which allows you to embed a registry value whereever normal constants are used. It is in the format: "{reg:HKxx\SubkeyName,ValueName|DefaultValue}".

You could do a conditional install see this: Can Inno Setup do a conditional installation - for example, proceed only if a certain registry key or file exists?