如何忽略f中的异常#

在正常程序执行期间,可能会发生异常。

如果我意识到这一点,只是想忽略它我如何在f中实现这一点?

这是我的代码,它编译时带有一个警告:

let sha = new SHA1CryptoServiceProvider()
let maxLength = 10000
let fileSign file = 
    let fs = File.OpenRead(file)
    let mutable res = (0L, [|0uy|])
    try
        let flLen = fs.Length
        let len = int (min (int64 maxLength) flLen)

        // read 'len' bytes        
        let mutable pos = 0
        while (pos < len) do
            let chunk = fs.Read(buf, pos, len - pos)
            pos <- pos + chunk

        // get signature            
        let sign = sha.ComputeHash(buf, 0, len)

        // store new result
        res <- (flLen, sign)        
    with
        | :? IOException as e -> e |> ignore
    finally 
        if (fs <> null) then
            fs.Dispose()
    res

警告是:
error FS0010: Unexpected keyword 'finally' in binding. Expected incomplete structured construct at or before this point or other token.

我想要的相应的c等价物是:

FileStream fs = null;
try
{
    fs = File.OpenRead(file);
    // ... other stuff
}
catch
{
    // I just do not specify anything
}
finally
{ 
    if (fs != null)
        fs.Dispose()
}

如果我忽略了 with 在F中,异常不会被忽略。