C# - 如何获取 oracle long 原始类型值
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C# - How to get oracle long raw type value
提问by Chicharito
How to get long raw type value with C#?
如何使用 C# 获取 long 原始类型值？
回答by Igby Largeman
Since you haven't posted any code, I don't know how much you know. I'm going to assume you already understand how to execute a query and get back a result set using OracleDataReader.
由于你还没有发布任何代码，我不知道你知道多少。我将假设您已经了解如何使用 OracleDataReader 执行查询并取回结果集。
There is one gotcha with LONG and LONG RAW columns. You must set the InitialLONGFetchSizeproperty of your OracleCommandto a non-zero value.
LONG 和 LONG RAW 列有一个问题。您必须将您的InitialLONGFetchSize属性设置为OracleCommand非零值。
The default value of InitialLONGFetchSizeis zero, which means no data will be retrieved for LONG or LONG RAW columns. If you set it to -1, all data will be retrieved . You might not want to do this for large values. If you set it to anything above zero, that's how many bytes will be intially fetched and cached.
的默认值InitialLONGFetchSize为零，这意味着不会检索 LONG 或 LONG RAW 列的数据。如果将其设置为 -1，则将检索所有数据。对于较大的值，您可能不想这样做。如果您将其设置为大于零的任何值，这就是最初获取和缓存的字节数。
You should read the documentationfor InitialLONGFetchSize, because there are some other details you need to know.
你应该阅读的文档的InitialLONGFetchSize，因为有你需要知道的一些其他细节。
回答by Mouzam Basheer
Here is Code to solve this issue.
这是解决此问题的代码。
Byte[] img;
con.Open();
OracleCommand command = new OracleCommand("Select Image as BLOBDATA FROM tbltestImage ", con);
command.InitialLONGFetchSize = -1;
OracleDataReader rdr = command.ExecuteReader();
DataTable dt = new DataTable();
dt.Load(rdr);
con.Close();
if (dt.Rows.Count > 0)
{
if (dt.Rows[0]["BLOBDATA"].ToString() != "")
{
img = (Byte[])dt.Rows[0]["BLOBDATA"];
MemoryStream ms = new MemoryStream(img);
Bitmap bitmap = new Bitmap(ms);
pictureBox2.Image = bitmap;
pictureBox2.SizeMode = PictureBoxSizeMode.StretchImage;
}
}
