C# App - How can you update source XML file from dataset/dataview?

[AHayes]

I've been searching online for a while now with no luck, so I'll try the friendly folk here.


_The Problem
I have a dataset/dataview that's getting its data from an XML file (which we're using sort-of like a database). I'm a little more used to contacting SQL servers instead of XML files, but have managed to read from the XML file and read/display the data. I thought I was able to change the data (from a form) as well, but realized the changes to the data were only in the "memory" version of the table and NOT the source document like I want.

This is a problem I ran into when I started using ADO.Net with SQL server, so I know the issue is simply filling in or updating the source file with the changes...I just don't know how to do that in the XML world. So I guess I'm looking for the XML equivalent to "SQLDataAdapter.Fill(DataSet)".


_The Code
Here's a sample of the code as I have it currently:

//Initialize dataset/dataview
DataSet dstMyDataset = new DataSet();
DataView dvwMyDataview = new DataView();
 
//Import XML
String strFilePath = Application.StartupPath;
dstMyDataset.ReadXmlSchema(strFilePath + "\\DataDef.xsd");
dstMyDataset.ReadXml(strFilePath + "\\Data.xml");
 
//Example edit of data from form:
dvwMyDataview[0]["Phone"] = txtPhone.Text;
 
//Saving
dstMyDataview.WriteXml(strFilePath + "\\Data.xml);

As always, I appreciate the help.

[r035198x]

I've been searching online for a while now with no luck, so I'll try the friendly folk here.


_The Problem
I have a dataset/dataview that's getting its data from an XML file (which we're using sort-of like a database). I'm a little more used to contacting SQL servers instead of XML files, but have managed to read from the XML file and read/display the data. I thought I was able to change the data (from a form) as well, but realized the changes to the data were only in the "memory" version of the table and NOT the source document like I want.

This is a problem I ran into when I started using ADO.Net with SQL server, so I know the issue is simply filling in or updating the source file with the changes...I just don't know how to do that in the XML world. So I guess I'm looking for the XML equivalent to "SQLDataAdapter.Fill(DataSet)".


_The Code
Here's a sample of the code as I have it currently:

//Initialize dataset/dataview
DataSet dstMyDataset = new DataSet();
DataView dvwMyDataview = new DataView();
 
//Import XML
String strFilePath = Application.StartupPath;
dstMyDataset.ReadXmlSchema(strFilePath + "\\DataDef.xsd");
dstMyDataset.ReadXml(strFilePath + "\\Data.xml");
 
//Example edit of data from form:
dvwMyDataview[0]["Phone"] = txtPhone.Text;
 
//Saving
dstMyDataview.WriteXml(strFilePath + "\\Data.xml);

As always, I appreciate the help.

I think you need the a filestream object as well as explained here.
Are you making changes to data/schema or both?

[AHayes]

I think you need the a filestream object as well as explained here.
Are you making changes to data/schema or both?

The changes being made are just to the data.



I tried the filestream approach, but it doesn't fix the issue. If the dataset itself isn't updated with the changes being made, how would changing how it gets written matter?


If I make a change to data within a DataView, how do I update the DataSet with said changes?

[r035198x]

The changes being made are just to the data.



I tried the filestream approach, but it doesn't fix the issue. If the dataset itself isn't updated with the changes being made, how would changing how it gets written matter?


If I make a change to data within a DataView, how do I update the DataSet with said changes?

AcceptChanges ?

[AHayes]

AcceptChanges ?

No. That's not doing anything either.


Just to add to the background:


I can launch my application, go to the form that the user will edit the data from (it fills in textboxes with a single record from the XML file so the user can change something) and edit something and "save" it.

I close my form and open it, and my change to the data is displayed correctly still. However, once I close the entire app and relaunch, it reverts back to the XML file--which was not actually changed.


Like I said, I had this issue once before, and I had to use SQLDataAdapter's Fill() method to have it update the dataset. Since I'm not using SQL server with my current app, I can't do this. I'm not sure if there's an XML equivalent.




Now, I've also tried displaying a test result FROM THE DATASET as such:
MessageBox.Show(dstConfig.Tables["TABLE_NAME"].Rows[0]["FEILD_NAME"].ToString());

..and that will display the data change correctly.



It feels like I'm missing a step....and I guess not a whole lot of people use XML like a database, since I can't seem to find a tutorial anywhere online that isn't connecting to SQL Server DB or Access or something.

[nateraaaa]

If you are using 2.0 there is a statement that may help you.
DataView.ToTable().WriteXml(...)

If not I believe you can only use the WriteXml method on a dataset. In your code you are trying to do the WriteXml method on a dataview.

See this discussion .

Nathan

[AHayes]

If you are using 2.0 there is a statement that may help you.
DataView.ToTable().WriteXml(...)

If not I believe you can only use the WriteXml method on a dataset. In your code you are trying to do the WriteXml method on a dataview.

See this discussion .

Nathan

Sorry. I didn't notice when I was changing the variable names in the sample code. I AM--in the REAL code--using DataSet.WriteXML(). It just doesn't seem to be writing.


I'll try the alternative method and get back to everyone. Thanks.

[AHayes]

Just FYI to close this thread out. I've found the issue was a lot simpler then I was making out to be (my apologies):

We were renaming our XML files to a different extension (to make it a little less obvious that it's just a giant XML file). Although it was still reading the XML file correctly into a dataset, I guess WriteXML() isn't as nice. Thus, it was never re-writing the file/saving changes.


So note to any kids out there: Don't rename your file extensions.