How to call a .net method with an output parameter?

问题

I just want to call the GenerateScript method of Microsoft.Data.Schema.ScriptDom.Sql.Sql100ScriptGenerator from PowerShell.

#C

public void GenerateScript(
    IScriptFragment scriptFragment,
    out string script
)

I found this, but I do not get it to work

$sg = new-object  Microsoft.Data.Schema.ScriptDom.Sql.Sql100ScriptGenerator

$sql = 'select * from PowerShell'

$out = ''
$sg.GenerateScript($sql, [ref] $out)

$out

this gives

Cannot find an overload for "GenerateScript" and the argument count: "2".
At line:6 char:19
+ $sg.GenerateScript <<<< ($sql, [ref] $out)
    + CategoryInfo          : NotSpecified: (:) [], MethodException
    + FullyQualifiedErrorId : MethodCountCouldNotFindBest

Edit:

Current version is

$sql = 'select * from PowerShell'

$sr = new-Object System.IO.StringReader($sql)

$sg =     new-object Microsoft.Data.Schema.ScriptDom.Sql.Sql100ScriptGenerator
$parser = new-object Microsoft.Data.Schema.ScriptDom.Sql.TSQL100parser($true)

$errors = ''
$fragment = $parser.Parse($sr,([ref]$errors))

$out = ''
$sg.GenerateScript($fragment,([ref][string]$out))

$out

But I get an error in line

$fragment = $parser.Parse($sr,([ref]$errors))



Cannot find an overload for "Parse" and the argument count: "2".
At line:11 char:26
+ $fragment = $parser.Parse <<<< ($sr,([ref]$errors))
    + CategoryInfo          : NotSpecified: (:) [], MethodException
    + FullyQualifiedErrorId : MethodCountCouldNotFindBest

I'm trying to convert

    IList<ParseError> errors;

    using (StringReader sr = new StringReader(inputScript))
    {
        fragment = parser.Parse(sr, out errors);
    }

Edit:

OK this works:

$sql = @'
select * from PowerShell -- a comment
where psRefnr = 1
'@
$options = new-object Microsoft.Data.Schema.ScriptDom.Sql.SqlScriptGeneratorOptions

$sr = new-Object System.IO.StringReader($sql)

$sg =     new-object Microsoft.Data.Schema.ScriptDom.Sql.Sql100ScriptGenerator($options)
$parser = new-object Microsoft.Data.Schema.ScriptDom.Sql.TSQL100parser($true)

$errors = $null
$fragment = $parser.Parse($sr,([ref]$errors))

$out = $null
$sg.GenerateScript($fragment,([ref]$out))

$out

and generates ( it removes the comment as intended )

SELECT *
FROM   PowerShell
WHERE  psRefnr = 1;

回答1:

I believe your issue is with your first parameter, which should be a IScriptFragment. You are passing a string.

You would need to pass something that derives from TSqlFragment. Using something like the TSql100Parser.ParseStatementList method, you will get a list of fragments.

EDIT: This blog post has a similar issue to your second error.

回答2:

Not entirely sure how this works with Powershell, but in normal C# you need to call an out parameter with the keyword "out" instead of the "ref" you have. Sorry if this is off base, but figured it might help.

来源：https://stackoverflow.com/questions/5276700/how-to-call-a-net-method-with-an-output-parameter

标签

.net

powershell

out