optional parameters must appear after all required parameters in c# [duplicate]

Answer 1

You need to move your optional parameters to the end of the parameter list:

from MSDN:

Optional parameters are defined at the end of the parameter list, after any required parameters. If the caller provides an argument for any one of a succession of optional parameters, it must provide arguments for all preceding optional parameters. Comma-separated gaps in the argument list are not supported. For example, in the following code, instance method ExampleMethod is defined with one required and two optional parameters.

public List GetIndentFilledInfo(
        List surveyFeedbacks, 
        bool hasupdate,
        string ddlevent,
        string indentType = null)

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