c# - 使用 Oledbconnection 时出现编译错误

Question

我在这里使用 OleDbConnection 作为连接字符串，但我在行中收到错误

if (conn.State == ConnectionState.Closed)

Error as CS0019: Operator '==' cannot be applied to operands of type 'System.Data.ConnectionState' and 'ConnectionState'

这是我的代码

protected void btnSave_Click(object sender, EventArgs e)
{
    DataTable dtExcel = new DataTable();
    dtExcel.Clear();
    string StrCount = String.Empty;
    string connString = "";
    HttpPostedFile File = FileUpload1.PostedFile;
    string strFileType = Path.GetExtension(FileUpload1.FileName).ToLower();
    string path = FileUpload1.PostedFile.FileName;
    string Filename = path.Substring(path.LastIndexOf("\\") + 1, path.Length - path.LastIndexOf("\\") - 1);
    path = Server.MapPath(@"~/Excels/" + "/" + Filename.ToString());

    File.SaveAs(path);
    if (strFileType.Trim() == ".xls")
    {
        connString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + path + ";Extended Properties=\"Excel 8.0;HDR=Yes;IMEX=2\"";
    }
    else if (strFileType.Trim() == ".xlsx")
    {
        connString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties=\"Excel 12.0;HDR=Yes;IMEX=2\"";
    }
    string query = "SELECT * FROM [Sheet 1$]";
    OleDbConnection conn = new OleDbConnection(connString);
    conn.Close();
    if (conn.State == ConnectionState.Closed)
        conn.Open();
    OleDbCommand cmd = new OleDbCommand(query, conn);
    OleDbDataAdapter daExcel = new OleDbDataAdapter(cmd);

    daExcel.Fill(dtExcel);
    conn.Close();}

不知道为什么？

我尝试了其他链接的解决方案，但没有帮助

Answer 1

在我看来，您的类名或属性名不明确。 ConnectionState 似乎有两个含义。

尝试在 ConnectionState 前加上其完整的命名空间:

if (conn.State == System.Data.ConnectionState.Closed)