Question

我尝试将图像从mssql varbinary（max）列导入iTextSharp。但它总是显示错误＆＃34; NullReferenceException＆＃34;在＆＃34; phrase.Add（imageChunk）＆＃34;

我的代码是：

Dim conn As New SqlConnection(ConfigurationManager.ConnectionStrings("dbconnection").ConnectionString)

Dim q As String = "select top 1  pic_id from pic"
Dim cmd As SqlCommand = New SqlCommand(q, conn)
conn.Open()
Dim sr As SqlDataReader = cmd.ExecuteReader

While sr.Read
    Dim byt() As Byte = CType(sr.Item("pic_id"), Byte())
    Dim ms As MemoryStream = New MemoryStream(byt)
    Dim sdi As System.Drawing.Image = System.Drawing.Image.FromStream(ms)
    Dim img As Image = Image.GetInstance(sdi, ImageFormat.Jpeg)

    Dim imageChunk As Chunk = New Chunk(img, 0, 0)
    phrase.Add(imageChunk)
End While

该列的数据类型是＆＃34; varbinary（max）＆＃34;数据是这样的：（0x89504E470D0A1A0A0000000D494 ....................）

Answer 1

你的变量＆＃34;短语＆＃34;没有设置，它没有/ null。确保传递正确的＆＃34;短语＆＃34;对你的方法很有可能解决你的问题。

将二进制文件转换为图像时出错

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