I'm trying to form a relationship parent-child between two datagridviews, but I'm getting this error:'table' argument cannot be null.Parameter name: table".

private DataTable Table_c; // Table_c is imported from a local database
private DataTable Table_a; // Table_a is imported from a local database
private DataSet tblDataSet;

private void Form1_Load(object sender, EventArgs e)
{
    this.table_aTableAdapter1.Fill(this.DBDataSet1.Table_a);

    this.table_cTableAdapter.Fill(this.DBDataSet1.Table_c);

    tblDataSet = new DataSet();
    tblDataSet.Tables.Add(Table_c);
    tblDataSet.Tables.Add(Table_a);


    tblDataSet.Relations.Add("Relation1",
        Table_c.Columns["Number"], Table_a.Columns["Number"]);

    BindingSource bsC = new BindingSource();
    bsC.DataSource = tblDataSet;
    bsC.DataMember = "Table_c";

    BindingSource bsA = new BindingSource();
    bsA.DataSource = bsC;
    bsA.DataMember = "Relation1";

    table_cDataGridView.DataSource = bsC;
    table_aDataGridView.DataSource = bsA; 
}