Here I will describe how to show data in nested datagrid using C# winforms

This is applicable to those cases where we have to display master and child content / rows.

Example Student Table

Here in this example we have list of Students  and inside we have details of student marks

Our purpose is to display this type of data using C#  Winforms

Steps and Code:

1. First we need to create Master and child tables.
2. To identify the relationship between tables we should have Primary and Foreign Keys in tables 
3. Here we are creating datatable for master and child tables.
4. Master table  (student)

                //Parent table
            DataTable dtstudent = new DataTable();
            dtstudent.Columns.Add("Student_ID", typeof(int));
            dtstudent.Columns.Add("Student_Name", typeof(string));
            dtstudent.Columns.Add("Student_RollNo", typeof(string));

5. Child Table (Student Marks)

//Child table
            DataTable dtstudentMarks = new DataTable();
            dtstudentMarks.Columns.Add("Student_ID", typeof(int));
            dtstudentMarks.Columns.Add("Subject_ID", typeof(int));
            dtstudentMarks.Columns.Add("Subject_Name", typeof(string));
            dtstudentMarks.Columns.Add("Marks", typeof(int)); 

f.  Understanding Relation ship between Master and child table

g.  In brief

dtstudent.StudentID = dtstudentMarks.StudentID 

Adding Rows to Master table (Student Table)

//Adding Rows
 
            dtstudent.Rows.Add(111, "Devesh", "03021013014");
            dtstudent.Rows.Add(222, "ROLI", "0302101444");
            dtstudent.Rows.Add(333, "ROLI Ji", "030212222");
            dtstudent.Rows.Add(444, "NIKHIL", "KANPUR");
 

i.  Adding Row to Child table (Student Marks table)

   // data for devesh ID=111
            dtstudentMarks.Rows.Add(111, "01","Physics", 99);
            dtstudentMarks.Rows.Add(111, "02","Maths", 77);
            dtstudentMarks.Rows.Add(111, "03","C#", 100);
            dtstudentMarks.Rows.Add(111, "01","Physics", 99);
 
 
            //data for ROLI ID=222
            dtstudentMarks.Rows.Add(222, "01", "Physics", 80);
            dtstudentMarks.Rows.Add(222, "02", "English", 95);
            dtstudentMarks.Rows.Add(222, "03", "Commerce", 95);
            dtstudentMarks.Rows.Add(222, "01", "BankPO", 99);

Adding master and child table to dataset.

DataSet dsDataset = new DataSet();
  dsDataset.Tables.Add(dtstudent);
  dsDataset.Tables.Add(dtstudentMarks);

Defining relationship between Master and child table

DataRelation Datatablerelation = new DataRelation("DetailsMarks", dsDataset.Tables[0].Columns[0], dsDataset.Tables[1].Columns[0],true);
            dsDataset.Relations.Add(Datatablerelation);

 l.  Adding Datagrid control in winforms

As per screen below we can add datagrid to winforms

Right click in tool bar -> choose item 

m.    Binding data

dataGrid1.DataSource = dsDataset.Tables[0]; 

n.      All code together

private void Form1_Load(object sender, EventArgs e)
        {
            //Parent table
            DataTable dtstudent = new DataTable();
            // add column to datatable  
            dtstudent.Columns.Add("Student_ID", typeof(int));
            dtstudent.Columns.Add("Student_Name", typeof(string));
            dtstudent.Columns.Add("Student_RollNo", typeof(string));
 
           
            //Child table
            DataTable dtstudentMarks = new DataTable();
            dtstudentMarks.Columns.Add("Student_ID", typeof(int));
            dtstudentMarks.Columns.Add("Subject_ID", typeof(int));
            dtstudentMarks.Columns.Add("Subject_Name", typeof(string));
            dtstudentMarks.Columns.Add("Marks", typeof(int));
           
 
 
            //Adding Rows
 
            dtstudent.Rows.Add(111, "Devesh", "03021013014");
            dtstudent.Rows.Add(222, "ROLI", "0302101444");
            dtstudent.Rows.Add(333, "ROLI Ji", "030212222");
            dtstudent.Rows.Add(444, "NIKHIL", "KANPUR");
 
                // data for devesh ID=111
            dtstudentMarks.Rows.Add(111, "01","Physics", 99);
            dtstudentMarks.Rows.Add(111, "02","Maths", 77);
            dtstudentMarks.Rows.Add(111, "03","C#", 100);
            dtstudentMarks.Rows.Add(111, "01","Physics", 99);
 
 
            //data for ROLI ID=222
            dtstudentMarks.Rows.Add(222, "01", "Physics", 80);
            dtstudentMarks.Rows.Add(222, "02", "English", 95);
            dtstudentMarks.Rows.Add(222, "03", "Commerce", 95);
            dtstudentMarks.Rows.Add(222, "01", "BankPO", 99);
 
 
 
            DataSet dsDataset = new DataSet();
            //Add two DataTables  in Dataset
 
            dsDataset.Tables.Add(dtstudent);
            dsDataset.Tables.Add(dtstudentMarks);
 
           
            DataRelation Datatablerelation = new DataRelation("DetailsMarks", dsDataset.Tables[0].Columns[0], dsDataset.Tables[1].Columns[0], true);
            dsDataset.Relations.Add(Datatablerelation);
            dataGrid1.DataSource = dsDataset.Tables[0];
 
        }

o. Running code

We will get following screen having expandable rows in datagrid.

p.      Expanding row to see details

q.      Click on DetailsMarks to get Marks details

r.        Details screen for student_Id=222 

s.       Go to back for Master details

Click on highlighted back button to go master detail form

t.        Main form

Conclusion 

We have learned how to show data in datagrid with master and child relationship.