读取 blob

Question

给段源码你参考一下.Response.Clear()
'Response.AddHeader("Content-Type",dr("文件类型").ToString(),filename=" & dr("文件名"))
dim  strFileName as string  = System.Web.HttpUtility.UrlEncode( System.Text.Encoding.UTF8.GetBytes(dr("文件名").tostring())) Response.AddHeader ("content-disposition", "attachment; filename=" &  strfilename)
Response.contenttype=dr("文件类型").ToString() Response.BinaryWrite(dr("文件内容"))

Answer 1

看看这个(仅供参考)：－－从数据库中获取 BLOB 值/// <summary>
/// 根据select command查询Blob大对象数据
/// </summary>
/// <param name="select">已设置好参数的Select Command</param>
/// <returns>byte数组</returns>
/// <res>取出大对象数据，如图片等。</res>
public byte[] ReadBlobData(IDbCommand select)
{
switch(dbType)
{
case DB.DbTypeClass.DBType.Oracle:
{
try
{
select.Connection=connOracle;
if ( select.Connection.State != ConnectionState.Open)
select.Connection.Open();
select.ExecuteNonQuery();
OracleLob lob = (OracleLob)((OracleParameter)select.Parameters[1]).Value;
if( lob.IsNull )
return null;
byte[] imgData = new byte[lob.Length];
lob.Read( imgData,0,(int)lob.Length);
return imgData;
}
catch//(Exception ex)
{
return null;
}
finally
{
select.Connection.Close();
}
}
case DB.DbTypeClass.DBType.SqlServer:
{
try
{
select.Connection=connSql;
if ( select.Connection.State != ConnectionState.Open)
select.Connection.Open();
select.ExecuteNonQuery();
byte[] imgData=(byte[])((SqlParameter)select.Parameters[1]).Value;
return imgData;
}
catch//(Exception ex)
{
return null;
}
finally
{
select.Connection.Close();
}
}
case DB.DbTypeClass.DBType.OleDB:
{
try
{
select.Connection=connSql;
if ( select.Connection.State != ConnectionState.Open)
select.Connection.Open();
select.ExecuteNonQuery();
byte[] imgData=(byte[])((OleDbParameter)select.Parameters[1]).Value;
return imgData;
}
catch//(Exception ex)
{
return null;
}
finally
{
select.Connection.Close();
}
}
default:
return null;
}

}

Answer 2

你将blob类型换成long raw类型在测试一下

Answer 3

dbType是数据库类型：
public enum DBType
{
Oracle,SqlServer,OleDb
}