使用本网站的以下语法检索来自数据库的图像文件路径时，我目前收到错误消息：
private void DisplayImages(DataRow row, string img, string ImagePath)
{
FileStream stream = new FileStream(ImagePath, FileMode.Open, FileAccess.Read);
byte[] ImgData = new byte[stream.Length];
stream.Read(ImgData, 0, Convert.ToInt32(stream.Length));
stream.Close();
row[img] = ImgData;
}
列名以Image数据类型命名nvarchar。我目前遇到的错误发布在下面
String 的 SourceColumn 'Image' 与 Byte[] 的 DataColumn 'Image' 之间存在不可转换的类型不匹配。
不要使用 nvarchar 类型，这里使用 BLOB 示例： http: //msdn2.microsoft.com/en-us/library/87z0hy49 (VS.80).aspx 代码片段
// Assumes that connection is a valid SqlConnection object.
SqlCommand command = new SqlCommand(
"SELECT pub_id, logo FROM pub_info", connection);
// Writes the BLOB to a file (*.bmp).
Stream stream;
// Streams the BLOB to the FileStream object.
BinaryWriter writer;
// Size of the BLOB buffer.
int bufferSize = 100;
// The BLOB byte[] buffer to be filled by GetBytes.
byte[] outByte = new byte[bufferSize];
// The bytes returned from GetBytes.
long retval;
// The starting position in the BLOB output.
long startIndex = 0;
// The publisher id to use in the file name.
string pubID = "";
// Open the connection and read data into the DataReader.
connection.Open();
SqlDataReader reader = command.ExecuteReader(CommandBehavior.SequentialAccess);
while (reader.Read())
{
// Get the publisher id, which must occur before getting the logo.
pubID = reader.GetString(0);
// Create a file to hold the output.
stream = new MemoryStream();
writer = new BinaryWriter(stream);
// Reset the starting byte for the new BLOB.
startIndex = 0;
// Read bytes into outByte[] and retain the number of bytes returned.
retval = reader.GetBytes(1, startIndex, outByte, 0, bufferSize);
// Continue while there are bytes beyond the size of the buffer.
while (retval == bufferSize)
{
writer.Write(outByte);
writer.Flush();
// Reposition start index to end of last buffer and fill buffer.
startIndex += bufferSize;
retval = reader.GetBytes(1, startIndex, outByte, 0, bufferSize);
}
// Write the remaining buffer.
writer.Write(outByte, 0, (int)retval - 1);
writer.Flush();
// Close the output file.
writer.Close();
stream.Close();
}
// Close the reader and the connection.
reader.Close();
connection.Close();
Image _Image = Image.FromStream(stream);
System.Windows.Controls.Image _WPFImage = new System.Windows.Controls.Image();
_WPFImage.Source = System.Windows.Media.Imaging.BitmapFrame.Create(stream);
// Assumes that connection is a valid SqlConnection object.
SqlCommand command = new SqlCommand(
"SELECT pub_id, logo FROM pub_info", connection);
// Writes the BLOB to a file (*.bmp).
Stream stream;
// Streams the BLOB to the FileStream object.
BinaryWriter writer;
// Size of the BLOB buffer.
int bufferSize = 100;
// The BLOB byte[] buffer to be filled by GetBytes.
byte[] outByte = new byte[bufferSize];
// The bytes returned from GetBytes.
long retval;
// The starting position in the BLOB output.
long startIndex = 0;
// The publisher id to use in the file name.
string pubID = "";
// Open the connection and read data into the DataReader.
connection.Open();
SqlDataReader reader = command.ExecuteReader(CommandBehavior.SequentialAccess);
while (reader.Read())
{
// Get the publisher id, which must occur before getting the logo.
pubID = reader.GetString(0);
// Create a file to hold the output.
stream = new MemoryStream();
writer = new BinaryWriter(stream);
// Reset the starting byte for the new BLOB.
startIndex = 0;
// Read bytes into outByte[] and retain the number of bytes returned.
retval = reader.GetBytes(1, startIndex, outByte, 0, bufferSize);
// Continue while there are bytes beyond the size of the buffer.
while (retval == bufferSize)
{
writer.Write(outByte);
writer.Flush();
// Reposition start index to end of last buffer and fill buffer.
startIndex += bufferSize;
retval = reader.GetBytes(1, startIndex, outByte, 0, bufferSize);
}
// Write the remaining buffer.
writer.Write(outByte, 0, (int)retval - 1);
writer.Flush();
// Close the output file.
writer.Close();
stream.Close();
}
// Close the reader and the connection.
reader.Close();
connection.Close();
Image _Image = Image.FromStream(stream);
System.Windows.Controls.Image _WPFImage = new System.Windows.Controls.Image();
_WPFImage.Source = System.Windows.Media.Imaging.BitmapFrame.Create(stream);