Display pdf file from postgresql to a datagridview using c#

Question

Hello again everyone, How can I retrieve and display the uploaded pdf/doc file from PostgreSQL to a datagridview in WinForms using C#? This is my first time using a PostgreSQL. Thanks, everyone.

Laxmidhar Sahoo · Answer

Do not use reader .Use dataset . if use reader then use it in while may access data if (rdr.Read()) { while(rdr.Reead()) { data_file = (byte[])rdr[0]; } }

Jes Sie · Answer

this is what I did but it says "parameter is not valid". Refer to code snippet below; private void DisplayFile() { byte [] data_file = null ; using (NpgsqlConnection con = ClassConnection.GetDbCon()) { using (NpgsqlCommand cmd = new NpgsqlCommand( "SELECT data_file FROM public.uploaded_file WHERE id = @id;" , con)) { cmd.CommandType = CommandType.Text; con.Open(); cmd.Parameters.AddWithValue( "@id" , NpgsqlTypes.NpgsqlDbType.Integer).Value = 2; NpgsqlDataReader rdr = cmd.ExecuteReader(); if (rdr.Read()) { data_file = ( byte [])rdr[0]; } rdr.Close(); if (data_file != null ) { using (MemoryStream productImageStream = new MemoryStream(data_file)) { ImageConverter imageConverter = new ImageConverter(); pictureBox1.Image = imageConverter.ConvertFrom(data_file) as Image; } } } } } How do I use your code?

Laxmidhar Sahoo · Answer

Hi You have to customize a gridview column as pdf which is derived from DataGridViewImageColumn or Display as image public Image byteArrayToImage( byte [] byteArrayIn) { MemoryStream ms = new MemoryStream(byteArrayIn); Image returnImage = Image.FromStream(ms); return returnImage; } void dataGridView_CellFormatting( object sender, DataGridViewCellFormattingEventArgs e) { // 2 - Salt, 3 - SecurePassword if (e.ColumnIndex == 2 ) { if (e.Value != null ) { byte [] array = ( byte [])e.Value; e.Value = byteArrayToImage(array); e.FormattingApplied = true ; } else e.FormattingApplied = false ; } }

Jes Sie · Answer

Hello Lax, below is what I did: private void btnFileUpload_Click( object sender, EventArgs e) { DialogResult result = openFileDialog1.ShowDialog(); if (result == DialogResult.OK) { string extension = Path.GetExtension(openFileDialog1.FileName); string fname = Path.GetFileName(openFileDialog1.FileName); switch (extension) { case ".doc" : case ".docx" : case ".pdf" : using (FileStream fs = new FileStream( "D:\Saved Images\" + fname, FileMode.Open, FileAccess.Read)) { using (BinaryReader pgReader = new BinaryReader( new BufferedStream(fs))) { byte [] ImgByteA = pgReader.ReadBytes(Convert.ToInt32(fs.Length)); using (NpgsqlConnection con = ClassConnection.GetDbCon()) { string query = "INSERT INTO public.uploaded_file(file_name, content_type, data_file) VALUES(@file_name, @content_type, @data_file); " ; using (var cmd = new NpgsqlCommand(query, con)) { cmd.CommandType = CommandType.Text; cmd.Parameters.AddWithValue( "@file_name" , fname); cmd.Parameters.AddWithValue( "@content_type" , extension); cmd.Parameters.AddWithValue( "@data_file" , NpgsqlTypes.NpgsqlDbType.Bytea).Value = ImgByteA; con.Open(); cmd.ExecuteNonQuery(); } } } } break ; } } }

Laxmidhar Sahoo · Answer

Hi How stored the file in postGreSQL . I mean you srored the file path of the pdf or in byte array or with some other format Thanks and Regards

Display pdf file from postgresql to a datagridview using c#

Answers (5)