AxHost.GetPictureFromIPicture()方法丢失，正在从MS Access数据库检索图片(附件)

Question

我正在尝试使用AxHost.GetPictureFromIPicture()从MS Access 2013数据库文件(*.accdb)中获取GIF图像(另存为附件类型)-将其转换为图像，以便我可以在PictureBox中显示它。但是方法不在那里！:(我是否遗漏了什么？我需要设置或安装smtg吗？

如果不进行转换，我会收到此错误：“无法将类型为'System.__ComObject‘的COM对象强制转换为类类型'System.Drawing.Image'”

我真的以正确的方式做了所有的事情吗？或者有更好的解决方案？请帮帮我。

DBEngine dbe = new DBEngine();
Database db = dbe.OpenDatabase("Database1.accdb", false, false, "");
Recordset rs = db.OpenRecordset("select solution from tab2 where id = 1", RecordsetTypeEnum.dbOpenDynaset, 0, LockTypeEnum.dbOptimistic);
rs.MoveFirst();

object o = rs.Fields[0].Value;
Image img = (Image)o; -> error
Image img = AxHost.GetPictureFromIPicture(o); - the method is missing
pictureBox1.Image = img;

rs.Close();

Answer 1

AxHost Class的文档中写道

通常不直接使用AxHost类。可以使用Windows Forms ActiveX控件导入程序(Aximp.exe)生成扩展AxHost的包装。

我必须承认我没有尝试过这种方法。据我所知，从Access数据库的附件字段中可靠地提取文件的唯一方法是使用ACE Field2对象的.SaveToFile()方法。在您的示例中，代码将如下所示：

public partial class Form1 : Form
{
    string tempFileName;
    Image img;

    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        DBEngine dbe = new DBEngine();
        Database db = dbe.OpenDatabase(@"C:\Users\Public\AttachmentsDB.accdb");
        Recordset rsMain = db.OpenRecordset(
                "select solution from tab2 where id = 1",
                RecordsetTypeEnum.dbOpenSnapshot);
        Recordset2 rsAttach = rsMain.Fields["solution"].Value;
        tempFileName = System.IO.Path.GetTempPath() + "\\" + rsAttach.Fields["FileName"].Value;
        try
        {
            System.IO.File.Delete(tempFileName);
        }
        catch { }
        Field2 fldAttach = (Field2)rsAttach.Fields["FileData"];
        fldAttach.SaveToFile(tempFileName);
        rsAttach.Close();
        rsMain.Close();
        db.Close();
        img = Image.FromFile(tempFileName);
        pictureBox1.Image = img;
    }

    private void Form1_FormClosed(object sender, FormClosedEventArgs e)
    {
        img.Dispose();
        System.IO.File.Delete(tempFileName);
    }

}