Show relational data in a second datagrid

  • Thread starter Thread starter Mikael Syska
  • Start date Start date
M

Mikael Syska

Hi,

I have 2 talbes in a DataSet, and made a DataRelation between the 2
tables in the DataSet.

One of the Tables are displayed in a datagrid, and when one of them is
selected in the datagrid I want its childcolumns to be displayed in a
second datagrid.

How can I filter the dataset or get only the related data into the
second datagrid?

I totally blank on this one.

I use ByteFX to connect to a mysql database.

Here are my code:
private void Form1_Load(object sender, System.EventArgs e)
{
MySqlConnection thisConnection = new MySqlConnection("Server=syska.dk;
Username=root; Password=supermand; Database=c-sharp;");

MySqlDataAdapter thisPollAdapter = new MySqlDataAdapter("SELECT * FROM
poll", thisConnection);

MySqlDataAdapter thisOptionAdapter = new MySqlDataAdapter("SELECT *
FROM pollOption", thisConnection);

thisPollAdapter.Fill(thisDataSet, "first");

thisOptionAdapter.Fill(thisDataSet, "second");

dataGrid.DataSource = thisDataSet.Tables["first"];

DataRelation thisRelation = new DataRelation("thisRelation",
thisDataSet.Tables[0].Columns["pollId"],
thisDataSet.Tables[1].Columns["pollId"]);

// MessageBox.Show( thisDataSet.Tables[1].ParentRelations. );

// her skal de columns smides ind som passer til det ID som er valgt i
det anden datagrid
// dataGrid1.DataSource =
}

As you can see, I havent made anything fancy yet, are this the right way
to go, or are there are better way of doing this, I dont want to get all
the data every time, I choose a new row in the first datagrid..

kind regards
Mikael Syska
 
Mikael,

It's relatively easy. For the data source on the child grid, set it to
the DataRelation object that relates the two grids.

Hope this helps.
 
Hey,

Fairly new to C#,

Can you give me a example

Can't seem to get the idea of how it knows witch item is selected in the
first datagrid, but you can probebly give me a breef description of it

kind regards
Mikael Syska
 
Mikael,

You would want to do this:

// The grid is named childDataGrid, the DataSet is named dataSet.
childDataGrid.DataSource = dataSet.Relations[0];

You can substitute the relation for the proper one. The data set knows
it is a relation and will select the appropriate rows.
 
Nicholas,

I have just tried what you said...

now the code look like this:
MySqlConnection thisConnection = new MySqlConnection("Server=syska.dk;
Username=root; Password=supermand; Database=c-sharp;");

MySqlDataAdapter thisPollAdapter = new MySqlDataAdapter("SELECT *
FROM poll", thisConnection);
MySqlDataAdapter thisOptionAdapter = new MySqlDataAdapter("SELECT * FROM
pollOption", thisConnection);

thisPollAdapter.Fill(thisDataSet, "first");
thisOptionAdapter.Fill(thisDataSet, "second");

dataGrid.DataSource = thisDataSet.Tables["first"];

DataRelation thisRelation = new DataRelation("thisRelation",
thisDataSet.Tables[0].Columns["pollId"],
thisDataSet.Tables[1].Columns["pollId"]);

// My other datagrid1, this seems to work but no data is displayed
dataGrid1.DataSource = thisDataSet.Relations["thisRelation"];

// This gives me a error.... System.IndexOutOfRangeException: Cannot
find relation 0
// dataGrid1.DataSource = thisDataSet.Relations[0];

Can u see any errors or other mistyped things, cause it aint working....

Its so damm annoying that it aint working :-(
 
Tried a little more, and came a little closer, added this line to the
code and the Relation comes in the first DataGrid, but I would prefer
the other option with 2 datagrids.....

thisDataSet.Relations.Add(thisRelation);

Hope u have a solution for me

thanks on advance
Mikael Syska

Mikael said:
Nicholas,

I have just tried what you said...

now the code look like this:
MySqlConnection thisConnection = new MySqlConnection("Server=syska.dk;
Username=root; Password=supermand; Database=c-sharp;");

MySqlDataAdapter thisPollAdapter = new
MySqlDataAdapter("SELECT * FROM poll", thisConnection);
MySqlDataAdapter thisOptionAdapter = new MySqlDataAdapter("SELECT * FROM
pollOption", thisConnection);

thisPollAdapter.Fill(thisDataSet, "first");
thisOptionAdapter.Fill(thisDataSet, "second");

dataGrid.DataSource = thisDataSet.Tables["first"];

DataRelation thisRelation = new DataRelation("thisRelation",
thisDataSet.Tables[0].Columns["pollId"],
thisDataSet.Tables[1].Columns["pollId"]);

// My other datagrid1, this seems to work but no data is displayed
dataGrid1.DataSource = thisDataSet.Relations["thisRelation"];

// This gives me a error.... System.IndexOutOfRangeException: Cannot
find relation 0
// dataGrid1.DataSource = thisDataSet.Relations[0];

Can u see any errors or other mistyped things, cause it aint working....

Its so damm annoying that it aint working :-(

Mikael,

You would want to do this:

// The grid is named childDataGrid, the DataSet is named dataSet.
childDataGrid.DataSource = dataSet.Relations[0];

You can substitute the relation for the proper one. The data set
knows it is a relation and will select the appropriate rows.
Click to expand...
Click to expand...
 
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