在VB.NET中使用LINQ to SQL检索图像 [英] Retrive image using LINQ to SQL in VB.NET

问题描述

Dim db As New DataContext("Data Source=.\SQLEXPRESS;Initial Catalog=DBMSTW;Integrated Security=True")
        Dim emp As Table(Of Employee) = db.GetTable(Of Employee)()
        Dim query = From p In emp _
                  Where p.emp_id = "E58" Select p
        For Each p In query
            EmpID.Text = p.emp_id
            EmpName.Text = p.emp_name
            If (p.gender = "F") Then
                Female.Checked = True
            Else
                Male.Checked = True
            End If
            EmpAge.Text = p.age
            Dim Img As Image
            Dim ImgByte As Byte() = Nothing

            Dim stream As MemoryStream
            ImgByte = CType(p.img_data, Byte())            
stream = New MemoryStream(ImgByte, 0, ImgByte.Length)
            Img = Image.FromStream(stream)
            EmpImg.Image = Img

        Next

在上面的代码中，带下划线的部分存在错误.我想将图像检索到图片框EmpImg中.但是我不知道如何将其转换为使用LINQ to SQL.

错误消息为

类型"System.Data.Linq.Binary"的值不能转换为字节的一维数组".

In Above Code There is Error in Underlined Part. I want to retrive image into picturebox EmpImg. But I dont know how to convert it into using LINQ to SQL.

Error Message is

Value of type ''System.Data.Linq.Binary'' cannot be converted to ''1-dimensional array of Byte''.

推荐答案

我在应用程序中有一个类似的用例，它被设置为将二进制图像数据的内容写入用户控件:

I have a similar use case in an application and this is set to write the contents of the binary image data to a user control:

imgBytes = imgRow.ImageData.ToArray
Using mStream As New System.IO.MemoryStream(imgBytes)
    Using qImg As System.Drawing.Image = System.Drawing.Image.FromStream(mStream)
        Response.ContentType = mimeDict(qImg.RawFormat.Guid).MimeType
        Response.BinaryWrite(imgBytes)
    End Using
End Using

不过，对于您的情况...只要更改一下就可以摆脱现实

For your situation, though...you may be able to get away with just changing

ImgByte = CType(p.img_data, Byte())

TO

TO

ImgByte = CType(p.img_data.ToArray, Byte())

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