WriteXML, ReadXML Issue with Table Name

Question

I have a program where I run a query and store data in a DataTable. I then allow the user to save that DataTable.WriteXML. The problem I have is that I want to read that saved file (XML file) into another DataTable with a different name - and it does not allow it! It gives me an error "Error while loading Results Table to File: Data Table: 'ImportTable' does not match to any DataTable in Source"

Now I believe this message is telling me that the XML contains a different table name than the DataTable I am trying to ReadXML into it. I have tried setting the TableName property to blank - but that does not make any difference.

So - my question is how do others get around this issue? I am using the standard DataTable.WriteXML(filename) - and DataTable.ReadXML method calls. AND due to some design issues - I do need to have the import DataTable named differently than the one used to export the data.

Is there a different way to write out and read in the data in the DataTable that will get around this issue?

Sample code - showing the issue In the form load - create two tables - one named Export the other Import. Create a structure for Export - and populate it with 10 records.

    private void Form_Main_Load(object sender, EventArgs e)
    {
        ExportTable = new DataTable("Export");
        ImportTable = new DataTable("Import");

        ExportTable.Columns.Add("ID", Type.GetType("System.Int32"));
        ExportTable.Columns.Add("Name", Type.GetType("System.String"));
        ExportTable.Columns.Add("Amount", Type.GetType("System.Int32"));

        // Populate the first one
        DataRow workRow;
        for (int i = 0; i <= 9; i++)
        {
            workRow = ExportTable.NewRow();
            workRow[0] = i;
            workRow[1] = "CustName" + i.ToString();
            workRow[2] = i;
            ExportTable.Rows.Add(workRow);
        }
    }

Then create two buttons - one for exporting the data - the other for importing the data.

    private void button_Export_Click(object sender, EventArgs e)
    {
        ExportTable.WriteXml("c:\\Temp\\TableOut.xml");
    }

    private void button_Import_Click(object sender, EventArgs e)
    {
        ImportTable.ReadXmlSchema("c:\\Temp\\TableOut.xml");
        ImportTable.ReadXml("c:\\Temp\\TableOut.xml");
    }

Run the program - export the data - then click on the Import button. When you do - you will get the error - "DataTable 'Import' does not match to any DataTable in source." Now - I realize it is because the XML has the Export table name embedded in the XML. In my case I need to import that data into a DataTable with a different name - and I am wondering how (and if) others have dealt withi this in the past? Did you manually change the name in the XML? Did you temporarily change the datatable name? OR is there another better way around this issue of trying to use the READXML method of a DataTable?

Answer 1

Ok - I have been playing around with this - and have a solution. Not sure it is the best (and I would appreciate any comments as to how I might do this better).

Basically what I had to do was write the XML out to a string reader - change the table name for the schema and the record elements. Both the <> and tags.
Then when I read it in - I had to do the reverse - basically read the file into a string - then change all the table names back to what I needed them to be. Then I had to write the file out to disk (temporary file) - and then use the ReadXML method to read that temp file and then delete the file. I am not sure why the ReadXML with a string reader did not work (it seems to be a valid parameter) - but I had found a few posts that stated there were issues with the READXML method and string readers - so I simply wrote it out to file and used READXML with the file name - and it worked fine.

I hope this helps others - even if it is not the 'best' solution - maybe someone else can improve on it.

Write XML

// Write XML
StringWriter sw = new StringWriter();
ResultDT.WriteXml(sw, XmlWriteMode.WriteSchema);
string OutputXML = sw.ToString();
// now replace the Table Name
OutputXML = OutputXML.Replace("<" + ResultDT.TableName + ">", "<" + "ExportTable" + ">");
OutputXML = OutputXML.Replace("</" + ResultDT.TableName + ">", "</" + "ExportTable" + ">");
OutputXML = OutputXML.Replace("MainDataTable=\"" + ResultDT.TableName + "\"", "MainDataTable=\"" + "ExportTable" + "\"");
OutputXML = OutputXML.Replace("name=\"" + ResultDT.TableName + "\"", "name=\"" + "ExportTable" + "\"");
System.IO.File.WriteAllText(fileName, OutputXML);

Read XML

// Read XML
InputXML = System.IO.File.ReadAllText(fileName);
// now replace the Table Name
InputXML = InputXML.Replace("<" + "ExportTable" + ">", "<" + ResultTable.TableName + ">");
InputXML = InputXML.Replace("</" + "ExportTable" + ">", "</" + ResultTable.TableName + ">");
InputXML = InputXML.Replace("MainDataTable=\"" + "ExportTable" + "\"", "MainDataTable=\"" + ResultTable.TableName + "\"");
InputXML = InputXML.Replace("name=\"" + "ExportTable" + "\"", "name=\"" + ResultTable.TableName + "\"");
string TempFileName = "TempDumpFile.idt";
System.IO.File.WriteAllText(TempFileName, InputXML);
ResultTable.ReadXmlSchema(TempFileName);
ResultTable.ReadXml(TempFileName);
System.IO.File.Delete(TempFileName);