How to store and load a `.EDP` file from a database in Windows Forms?

In the WinForms Diagram Control, you can store and load a .EDP file from a database. First, use a SaveFileDialog to select the location for saving the file. Next, serialize the symbol palette using a BinaryFormatter and save the content of the file. Then, insert this content into a SQL database using an INSERT command. To load the file, execute a SELECT command to retrieve the file’s content from the database, write the binary data to a file, and use the LoadPalette method to load the symbol palette from this file. This process allows you to manage symbol palette files directly from the database, ensuring efficient storage and retrieval. Below, we have provided a code example to demonstrate how to achieve this.

Code Snippet

Save File:

           SaveFileDialog savePaletteDialog = new SaveFileDialog();
           savePaletteDialog.Filter = "EDP Files|*.edp|All Files|*.*";
           savePaletteDialog.Title = "Save a EDP File";
           if (savePaletteDialog.ShowDialog(this) == DialogResult.OK)
           {
               SymbolPalette symbolPalette = paletteGroupBar1.CurrentSymbolPalette;
               string strSavePath = savePaletteDialog.FileName;
               if (symbolPalette != null)
               {
                   FileStream fStream = new FileStream(strSavePath, FileMode.OpenOrCreate, FileAccess.Write);
                   BinaryFormatter formatter = new BinaryFormatter();
                   formatter.Serialize(fStream, symbolPalette);
                   fStream.Close();

                   string filePath = strSavePath;
                   string fileContents = File.ReadAllText(filePath);

                   using (SqlConnection connection = new SqlConnection("your connection string")) // Using your proper connection string value to execute.
                   {
                       SqlCommand command = new SqlCommand("INSERT INTO FileTable (FileName, FileContents) VALUES (@FileName, @FileContents)” , connection);

                                                   command.Parameters.AddWithValue("@FileName", Path.GetFileName(filePath));

                       command.Parameters.AddWithValue("@FileContents", fileContents);
                       connection.Open();
                       command.ExecuteNonQuery();
                   }
               }
           }



Load File:

           string fileName = "example.edp"; // Replace with the file name you want to load
           string filePath = "D:\\example.edp"; // Replace with the file path you want to save the file to

           using (SqlConnection connection = new SqlConnection("your connection string")) // Using your proper connection string value to execute.
           {
               SqlCommand command = new SqlCommand("SELECT FileContents FROM FileTable WHERE FileName = @FileName", connection);
               command.Parameters.AddWithValue("@FileName", fileName);

               connection.Open();

               using (SqlDataReader reader = command.ExecuteReader())
               {
                   if (reader.Read())
                   {
                       byte[] fileContents = (byte[])reader["FileContents"];
                       File.WriteAllBytes(filePath, fileContents);
                   }
               }
           }

           this.paletteGroupBar1.LoadPalette("D:\\example.edp"); // Use the exact location of the retrieved file location to load the palette. 
           

Conclusion:

I hope you enjoyed learning about How to store and load a .EDP file from a database in Windows Forms

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