Question

我有一列将图片存储在MS Access数据库中。在该列中，右键单击它并插入文件中的图片对象并在列中显示“包装”。

想法是将图片从文件上传到访问数据库的“ pic”列中，并使用“ querypic”表适配器查询，参数为“ comboname.text”，以返回图片并将其作为二进制存储在数组的字节中

但是当我将其转换为图像时出现错误

System.ArgumentException：'参数无效。

我检查了我的b（）字节数组，结果为{length = 40276} 有人可以帮我吗？

Private Sub cmdSelect_Click(sender As Object, e As EventArgs) Handles cmdSelect.Click
        Dim facultytabeladapt As New CSE_DEPTDataSetTableAdapters.FacultyTableAdapter
        Dim b() As Byte
        Dim s As String
        b = facultytabeladapt.querypic(ComboName.Text)

        PhotoBox.Image = b21(b)


    End Sub
    Private Function b21(ByVal b() As Byte) As Image

        Dim imgc As New ImageConverter

        Dim imgpic As Image = CType(imgc.ConvertFrom(b), Image) 'it has error "System.ArgumentException: 'Parameter is not valid."
        Return imgpic
    End Function

这可能是由于我直接上传以访问而不是RAW二进制文件的图片中的OLEDB对象

编辑： querypic是

SELECT        pic
FROM            Faculty
WHERE        (faculty_name = ?)

其中faculty_name是comboname.text

Answer 1

如果已经有字节数组，请从字节数组创建一个内存流，然后从该流创建一个映像。不要忘记添加Import System.IO来使用MemoryStream类。

Private Function b21(ByVal b() As Byte) As Image

    Dim ms As New MemoryStream(b) ' create memory stream from byte array
    Return Image.FromStream(ms) ' create image from memory stream

End Function

完整代码：

Imports System.IO
Imports System.Drawing.Imaging

Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        Dim b() As Byte
        b = ReadImage(Environment.GetFolderPath(Environment.SpecialFolder.MyPictures) & "\test.png")
        PhotoBox.Image = b21(b)

    End Sub

    Private Function b21(ByVal b() As Byte) As Image

        Dim ms As New MemoryStream(b) ' create memory stream from byte array
        Return Image.FromStream(ms) ' create image from memory stream

    End Function

    ''' <summary>
    ''' This function reads a file and returns a byte array
    ''' </summary>
    ''' <param name="file">A file in full path name</param>
    ''' <returns>A byte array of the image</returns>
    Private Function ReadImage(file As String) As Byte()

        Dim image As Image = Image.FromFile(file) ' read image from file
        Dim ms As New MemoryStream ' prepare a memory stream
        image.Save(ms, ImageFormat.Png) ' save the image into memory stream
        Return ms.ToArray() ' return byte array

    End Function

End Class

VB将图像从二进制转换为图像，参数错误

1 个答案: