Issue with dynamically contruct an INSERT statement - using vb code - that uploads a file into a database

Ok, here an issue I'm facing here:

As part of the project requirements I'm working on I need to upload a file to a database tabl, and to dynamically build my INSERT statement that uploads that file using vb.net.

Here is what I have:

I have a database table called "Attachments", it's design is as follows:

Column (1) Label = "ID"
Column (1) type = PRIMARY KEY
Column (1) Data-Type = "int"


Column (2) Label = "AttachmentContent"
Column (2) type = NORMAL
Column (2) Data-Type = "varbinary(MAX)"


So now, if I want to insert a record into this table, I can do so like this in my VB code:

Dim MC as new MainClass
MC.DB("INSERT INTO Attachments (AttachmentContent) VALUES (XXXXXXXXXXXXXXXXXXXXXXX)")

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See attachment "DB_CLASS.txt" that defines "MainClass"

Now, my issue is with the XXXXXXXXXXXXXXXXXXXXXXX above in my code

I tried to do it this way:

Dim filePath As String = "C:\Some_File.gif"
Dim fs As FileStream = New FileStream(filePath, FileMode.Open, FileAccess.Read)
Dim br As BinaryReader = New BinaryReader(fs)
Dim bytes As Byte() = br.ReadBytes(Convert.ToInt32(fs.Length))
br.Close()
fs.Close()
MC.DB("INSERT INTO Attachments (AttachmentContent) VALUES ('"+bytes.toString+"')")

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It gives me an error because the insert statement that the system tries to execute becomes like this at run time:

INSERT INTO Attachments (AttachmentContent) VALUES ('System.Byte[]')

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What am I missing here?
DB_CLASS.txt
Hussein ZahranAsked:
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Karthik RamachandranCommented:
Try something like this
query = "INSERT INTO student (AttachmentContent) VALUES (@AttachmentContent)"
Using conn as New SqlConnection("connectionStringHere")
    Using comm As New SqlCommand()
        With comm
            .Connection = conn
            .CommandType = CommandType.Text
            .CommandText = query
            .Parameters.AddWithValue("@AttachmentContent", bytes.toString())
        End With
                Try
                    conn.open()
                    comm.ExecuteNonQuery()
                Catch(ex as SqlException)
                    MessageBox.Show(ex.Message.ToString(), "Error Message")
                End Try
    End Using
End USing

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Hussein ZahranAuthor Commented:
I'm not allowed to execute the SQL statement like this due to some other requirements. Therefore; I mentioned that I need to construct the SQL statement through concatenaiton of strings.

So, all I need is how do I pass the bytes into the "INSERT INTO Attachments (AttachmentContent) VALUES (XXXXXXXXXXXXXXXXXXXXXXX)" string in place of the 'XXXXXXXXXXXXXXXXXXXXXXX'
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Hussein ZahranAuthor Commented:
Just to further explain why I can't use the code you're suggesting is that because I don't have access to change the definition of the MainClass.DB method, and that MainClass.DB method is the only way I can read/write from/to a database, and I'm not allowed to create my own method to read/write from/to a database.
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louisfrCommented:
To get a string out of a byte array, you need to use the correct Encoding object.
If your array contains UTF-8 bytes, you can get the string with:
Dim decodedString = Encoding.UTF8.GetString(bytes)

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Hussein ZahranAuthor Commented:
Louisfr

I tried what you suggested like this:

"INSERT INTO Attachments (AttachmentContent) VALUES (System.Text.Encoding.UTF8.GetString(bytes))"

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it gave me an error, I think my MC.DB() method expects something like this format "0x424D2E30140000.....etc." for the [AttachmentContent] column in Attachments table

Any idea?
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Hussein ZahranAuthor Commented:
I got it, the following function converts my "bytes" variable into a hexadec. format:

    Private Function BytesToString(ByVal Input As Byte()) As String
        Dim Result As New System.Text.StringBuilder(Input.Length * 2)
        Dim Part As String
        For Each b As Byte In Input
            Part = Conversion.Hex(b)
            If Part.Length = 1 Then Part = "0" & Part
            Result.Append(Part)
        Next
        Return "0x" + Result.ToString()
    End Function

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It works now
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Hussein ZahranAuthor Commented:
I searched further in the net and I found this solution which now works for me
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