Updating Database using Datagrid in C#

just working on the something lately need help i m again stuck here.... i m retrieving values from database using datagrid and i want to update the database using that similar datagrid but somehow i m having trouble, can anyone guide me how to do that..... i mean when the query is executed and selected data is retrieved if the user wants to update something he/she can do it at the datagrid in which value is being displayed....

if (textBox1.Text != ""|| textBox1.Text==null)
        {
            textBox3.Enabled = false;
            dateTimePicker1.Enabled = false;
            dateTimePicker2.Enabled = false;
            String txt = textBox1.Text;
            dataGridView1.DataSource = null;
            dataGridView1.Rows.Clear();
            dataGridView1.Refresh();

            OleDbDataAdapter dAdapter = new OleDbDataAdapter("SELECT * FROM [BDetails] WHERE ([BranchCode] = '" + @txt + "')", connParam);
            OleDbCommandBuilder cBuilder = new OleDbCommandBuilder(dAdapter);


             dataTable = new DataTable();
            DataSet ds = new DataSet();

            dAdapter.Fill(dataTable);

            if (dataTable.Rows.Count > 0)
            {
                for (int i = 0; i < dataTable.Rows.Count; i++)
                {
                    dataGridView1.Rows.Add(dataTable.Rows[i][0], dataTable.Rows[i][1], dataTable.Rows[i][2], dataTable.Rows[i][3], dataTable.Rows[i][4], dataTable.Rows[i][5], dataTable.Rows[i][6], dataTable.Rows[i][7], dataTable.Rows[i][8], dataTable.Rows[i][11], dataTable.Rows[i][12]);

                }

            }// end inner if
            else
            {
                MessageBox.Show("No Record Found");
                textBox3.Enabled = true;
                dateTimePicker1.Enabled = true;
                dateTimePicker2.Enabled = true;
            }// end inner else


        }// end outer if
        else 
        {
            MessageBox.Show("Please Enter Branch Code");
            bookConn.Close();

        }// end outer else

i m desperate guys help me

private void button8_Click(object sender, EventArgs e) { ReadData(); // SaveData();

    }// end function

    void ReadData()
    {
        this.ds = new DataSet();
      //  string connString = "CONNICTION STRING GOES HERE";
        dAdapter = new OleDbDataAdapter("select * from BDetails", connParam);
        this.dAdapter.Fill(this.ds,"[BDetails]");
        this.ds.AcceptChanges();
        //set the table as the datasource for the grid in order to show that data in the grid
        this.dataGridView1.DataSource = ds.DefaultViewManager;
    }// end function

    void SaveData()
    {
        DataSet changes = this.ds.GetChanges();
        if (changes != null)
        {
            //Data has changes. 
            //use update method in the adapter. it should update your datasource
            int updatedRows = this.dAdapter.Update(changes);
            this.ds.AcceptChanges();
        }
    }// end function

Well Abeer. there are really many ways to work with data and in a lot of times it is a developer preference to work one way or another. From your question, I can see that might be new to working with ADO.NET so I would suggest you do some reading on working with data in .NET (DataTables, DataSets, DataGrids, DataAdapters, Data Binding, ... etc)

I think (from my short experience) the simplest way to read and write data from and to data source is to use a DataAdapter to read the data into a dataset and then set the dataset as the datasource for a gridview where a user can edit. to write back the changes, just use the update method in the adapter. here is a sample code

DataSet ds;
OleDbDataAdapter dataAdapter;
void ReadData()
    {
        this.ds = new DataSet();
        string connString = "CONNICTION STRING GOES HERE";
        this.dataAdapter = new OleDbDataAdapter("QUERY GOES HERE", connString);
        this.dataAdapter.Fill(this.ds, "TABLE1");
        this.ds.AcceptChanges();
        //set the table as the datasource for the grid in order to show that data in the grid
        this.dataGridView1.DataSource = ds.DefaultViewManager;
    }

    void SaveData()
    {
        DataSet changes = this.ds.GetChanges();
        if (changes != null)
        {
            //Data has changes. 
            //use update method in the adapter. it should update your datasource
            int updatedRows = this.dataAdapter.Update(changes);
            this.ds.AcceptChanges();
        }
    }

see the following as it gives a longer sample about using DataGrid control

http://www.codeproject.com/Articles/9986/Using-the-DataGrid-Control

and for some intro on DataTable, DataSets and DataGrids see

http://www.codeproject.com/Articles/6179/A-Practical-Guide-to-NET-DataTables-DataSets-and-D