我试图将图片从图片框保存到访问数据库 [英] Am trying to save image from picture box to access database
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问题描述
Whenever i try to save picture from picturebox to access database i usually get this error message "An unhandled exception of type 'System.ArgumentNullException' occurred in mscorlib.dll
Additional information: Path cannot be null."
这是我保存到数据库的代码
This is my code for saving to database
private void cmdSave_Click(object sender, EventArgs e)
{
int rowCount;
rowCount = num.Next();
// OpenFileDialog f1 = new OpenFileDialog();
// f1.ShowDialog();
// picImageDisplay.ImageLocation = f1.FileName;
//save the image to the database
OleDbCommand cmd = new OleDbCommand();
cmd.Connection = DBConnection;
//creating a filestream and streamreader converting the pictures
// to binary before saving to the database
FileStream stream = null;
StreamReader reader = null;
stream = new FileStream(picPreview.ImageLocation, FileMode.Open, FileAccess.Read, FileShare.Read);
reader = new StreamReader(stream);
byte[] fbyteArray = new byte[stream.Length];
stream.Read(fbyteArray, 0, Convert.ToInt32(stream.Length));
if(cboCoordinateLabel.Text=="Artery")
{
cmd.CommandText = "INSERT INTO artery VALUES(@image_id,@coordinate,@image)";
cmd.Parameters.Add("@image_id", OleDbType.Integer).Value = rowCount;
cmd.Parameters.Add("@coordinate", OleDbType.VarChar).Value = coordinate;
cmd.Parameters.Add("@image", OleDbType.Binary, Convert.ToInt32(stream.Length)).Value = fbyteArray;
DBConnection.Open();
}
else if(cboCoordinateLabel.Text=="Vein")
{
cmd.CommandText = "INSERT INTO veins VALUES(@id,coordinate,@image)";
cmd.Parameters.Add("@image_id", OleDbType.Integer).Value = rowCount;
cmd.Parameters.Add("@coordinate", OleDbType.VarChar).Value = coordinate;
cmd.Parameters.Add("@image", OleDbType.Binary, Convert.ToInt32(stream.Length)).Value = fbyteArray;
DBConnection.Open();
}
else
{
MessageBox.Show("Please select an option from the coordinate label to proceed");
}
try
{
cmd.ExecuteNonQuery();
MessageBox.Show("Record has been saved");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message.ToString());
MessageBox.Show(ex.StackTrace.ToString());
}
finally
{
DBConnection.Close();
}
}
推荐答案
看看这个：为什么我得到参数无效。我从数据库中读取图像时出现异常？ [ ^ ] - 它适用于SQL Server而不是Access，但它与OleDBConnection和命令完全相同。
Have a look at this: Why do I get a "Parameter is not valid." exception when I read an image from my database?[^] - it's for SQL Server rather than Access but it's exactly the same process with OleDBConnection and command instead.
private void cmdSave_Click（object sender，EventArgs e）
{
arteryCount ++;
veinCount ++;
if（cboCoordinateLabel.Text！=）
{
if（cboCoordinateLabel.Text ==Artery）
{
尝试
{
//使用MemoryStream
MemoryStream ms = new MemoryStream（）;
pi cPreview.Image.Save（ms，System.Drawing.Imaging.ImageFormat.Jpeg）;
byte [] photo_aray = new byte [ms.Length];
ms。位置= 0;
ms。阅读（photo_aray，0，photo_aray.Length）;
//保存数据
cmd.CommandText =插入动脉值（@ image_id，坐标，图像）;
cmd.Parameters.Add（@ image_id，OleDbType.Integer）.Value = arteryCount;
cmd.Parameters.Add（@ coordinate，OleDbType.VarChar）.Value = coordinate;
cmd.Parameters.AddWithValue（@ image，photo_aray）;
DBConnection.Open（）;
cmd.Connection = DBConnection;
cmd.ExecuteNonQuery（）;
MessageBox.Show（记录已经已保存）;
}
catch（例外情况）
{
MessageBox.Show（ex.Message.ToString（））;
MessageBox.Show（ex.StackTrace.ToString（））;
}
终于
{
DBConnection.Close（）;
}
$ / $
}
其他
{
试试
{
//使用MemoryStream
MemoryStream ms = new MemoryStream（）;
picPreview.Image.Save（ms，System.Drawing.Imaging.ImageFormat.Jpeg ）;
byte [] photo_aray = new byte [ms .Length];
ms.Position = 0;
ms。阅读（photo_aray，0，photo_aray.Length）;
//保存数据
cmd.CommandText =插入静脉值（@ image_id，坐标，图像）;
cmd.Parameters.Add（ @image_id，OleDbType.Integer）.Value = veinCount;
cmd.Parameters.Add（@ coordinate，OleDbType.VarChar）.Value = coordinate;
cmd.Parameters.AddWithValue（@ image，photo_aray）;
DBConnection.Open（）;
cmd.Connection = DBConnection;
cmd.ExecuteNonQuery（）;
MessageBox.Show（记录已保存）;
}
catch（Excepti在前）
{
MessageBox.Show（ex.Message.ToString（））;
MessageBox.Show（ex.StackTrace.ToString （））;
}
终于
{
DBConnection.Close（）;
}
}
}
//如果组合框是空的
else
{
MessageBox.Show（请从坐标标签中选择一个选项继续）;
}
}
private void cmdSave_Click(object sender, EventArgs e)
{
arteryCount++;
veinCount++;
if(cboCoordinateLabel.Text != "")
{
if(cboCoordinateLabel.Text=="Artery")
{
try
{
//using MemoryStream
MemoryStream ms = new MemoryStream();
picPreview.Image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
byte[] photo_aray = new byte[ms.Length];
ms.Position = 0;
ms.Read(photo_aray, 0, photo_aray.Length);
//save data
cmd.CommandText = "insert into artery values(@image_id,coordinate,image)";
cmd.Parameters.Add("@image_id", OleDbType.Integer).Value = arteryCount;
cmd.Parameters.Add("@coordinate", OleDbType.VarChar).Value = coordinate;
cmd.Parameters.AddWithValue("@image", photo_aray);
DBConnection.Open();
cmd.Connection = DBConnection;
cmd.ExecuteNonQuery();
MessageBox.Show("Record has been saved");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message.ToString());
MessageBox.Show(ex.StackTrace.ToString());
}
finally
{
DBConnection.Close();
}
}
else
{
try
{
//using MemoryStream
MemoryStream ms = new MemoryStream();
picPreview.Image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
byte[] photo_aray = new byte[ms.Length];
ms.Position = 0;
ms.Read(photo_aray, 0, photo_aray.Length);
//save data
cmd.CommandText = "insert into vein values(@image_id,coordinate,image)";
cmd.Parameters.Add("@image_id", OleDbType.Integer).Value = veinCount;
cmd.Parameters.Add("@coordinate", OleDbType.VarChar).Value = coordinate;
cmd.Parameters.AddWithValue("@image", photo_aray);
DBConnection.Open();
cmd.Connection = DBConnection;
cmd.ExecuteNonQuery();
MessageBox.Show("Record has been saved");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message.ToString());
MessageBox.Show(ex.StackTrace.ToString());
}
finally
{
DBConnection.Close();
}
}
}
//if the combo box is empty
else
{
MessageBox.Show("Please select an option from the coordinate label to proceed");
}
}
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