从对象类型System.Drawing.Bitmap到已知的托管提供程序本机类型VB.NET不存在映射 [英] No mapping exists from object type System.Drawing.Bitmap to a known managed provider native type, VB.NET

问题描述

将图片从PictureBox1保存到SQL Server数据库时遇到问题，我进行了研究，发现我必须将图片转换为字节数组才能执行此操作，但是我不知道该怎么做.在我尝试编辑的代码中应用它.当我单击保存按钮时，出现此错误:No mapping exists from object type System.Drawing.Bitmap to a known managed provider native type.

I have a problem saving images from PictureBox1 to my SQL server database, I've done my research and found out that I have to convert my image to a byte array in order to do that but I don't know how to apply it in this code that I'm trying to edit. When I click on the save button I get this error: No mapping exists from object type System.Drawing.Bitmap to a known managed provider native type.

我认为这与将图像插入数据库有关，因此我将向您展示与之相关的代码片段.

I think it has something to do with inserting the image to the database so I'll show you code snippets that are related to it.

这是具有其属性的类:

Friend Class PersonFile
    Private _NewID As String

 Private _PersonID As String
    Friend Property PersonID() As String
        Get
            Return _PersonID
        End Get
        Set(ByVal Value As String)
            _PersonID = Value
        End Set
    End Property
 Private _Photo As Image
    Friend Property Photo() As Image
        Get
            Return _Photo
        End Get
        Set(ByVal Value As Image)
            _Photo = Value
        End Set
    End Property

这是插入功能:

Friend Class PersonFileDB
 Friend Function DXInsertFile(ByVal cItem As PersonFile) As PersonFile
        Dim cReturn As New PersonFile

 Using oleCON As New SqlConnection(AppVariables.GConnectionString)
            oleCON.Open()

 Dim n1 As String = ""
            n1 = CreateNewID()
            cItem.PersonID = n1

            Dim xSQL As New StringBuilder
            xSQL.AppendLine(" INSERT INTO PersonData ")
            xSQL.AppendLine("( ")
            xSQL.AppendLine(" PersonID, ")
            xSQL.AppendLine(" Photo, ")
            ''Other code...
            xSQL.AppendLine("VALUES ( ")
            xSQL.AppendLine(" @PersonID, ")
            xSQL.AppendLine(" @Photo, ")
            ''Other code...

            Dim oleComm As New SqlCommand(xSQL.ToString, oleCON)
            With oleComm.Parameters
                .AddWithValue(" @PersonID, ", cItem.PersonID)
                .AddWithValue("@Photo", cItem.Photo)
            ''Other code...
            End With

            Dim n As Integer
            n = oleComm.ExecuteNonQuery()
            If n <> 0 Then
                cItem.Updated = True
                SaveNewID(CInt(cItem.PersonID))
                cReturn = cItem
            End If
 End Using
 Return cReturn
End Function

这是点击事件:

Private CurrPerson As New PersonFile

Private Sub cmdPersonSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdPersonSave.Click

        CurrPerson.Photo = PictureBox1.Image
        ''Other code...
  Dim cdb As New PersonFileDB

        Select Case cmdPersonSave.Text
            Case "Add"
                UIClear()
                UISetControls(False)
                cmdPersonSave.Text = "Save"
                cmdPersonUpdate.Text = "Cancel"
                cmdPersonDelete.Enabled = False
                cmdSearch.Enabled = False
            Case "Save"
                If EditMode Then
                    CurrPerson = cdb.DXUpdateFile(CurrPerson)
                    EditMode = False
                Else
                    CurrPerson = cdb.DXInsertFile(CurrPerson)
                End If
                If CurrPerson.Updated Then
                    BindGrid(CurrPerson.PersonID)
                    UISetControls(True)
                End If
                cmdPersonSave.Text = "Add"
                cmdPersonUpdate.Text = "Edit"
                cmdPersonDelete.Enabled = True
                cmdSearch.Enabled = True
                UISetControls(True)
        End Select
        End Sub

推荐答案

在SQL SERVER数据库中，数据类型为 IMAGE .将该列的数据类型保持为 IMAGE .

In SQL SERVER database have datatype IMAGE. Keep the column datatype as IMAGE.

您可以使用以下示例代码并将Image传递给以下函数，该函数将图像转换为字节以存储在数据库中.

You can use the following sample code and pass Image to the below function which converts the image to byte to store in database.

public static byte[] ImageToByte2(Image img)
        {
            byte[] byteArray = new byte[0];
            using (MemoryStream stream = new MemoryStream())
            {
                img.Save(stream, System.Drawing.Imaging.ImageFormat.Png);
                stream.Close();

                byteArray = stream.ToArray();
            }
            return byteArray;
        }

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