C# Issue: How do I save changes made in a DataGridView back to the DataTable used?

Question

I get a DataTable from a DataSet and then bind that DataTable to a DataGridView. Once the user edits the information on the DataGridView how do I take those changes and put them back into a DataTable that was used that I can then put back into my DataSet?

I want to make a Save Button on my DataGrid that when pressed actually saves the changes.

I don't if I can get anymore specific than that, because it is a fairly simple question.

Thanks in advance!

Let me know if you need me to elaborate more.

Nyssa

Answer 1

If you are using data-binding to a DataGridView, then you are already updating the DataTable / DataSet. If you mean changes down to the database, then that is where adapters come into play.

Here's an example:

using System;
using System.Data;
using System.Linq;
using System.Windows.Forms;
static class Program
{
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();

        DataSet set = new DataSet();
        DataTable table = set.Tables.Add("MyTable");
        table.Columns.Add("Foo", typeof(int));
        table.Columns.Add("Bar", typeof(string));

        Button btn;
        using (Form form = new Form
        {
            Text = "DataGridView binding sample",
            Controls =
            {
                new DataGridView {
                    Dock = DockStyle.Fill,
                    DataMember = "MyTable",
                    DataSource = set
                },
                (btn = new Button {
                    Dock = DockStyle.Bottom,
                    Text = "Total"
                })
            }
        })
        {
            btn.Click += delegate
            {
                form.Text = table.AsEnumerable().Sum(
                    row => row.Field<int>("Foo")).ToString();
            };
            Application.Run(form);
        }

    }
}

Twophase

My god you know what you are talking about! Will you please look at my other question and help me out it seems you may be my only hope! #518739. Thanks! Ill see if this works for me. – Nyssa

That answered my question right there though. Whatever DataTable i've bound to the DataGrid is already being changed. Now if I could only figure out how to put that DataTable back into the Access .MDB file it came from. :/ Thanks! – Nyssa

Well, I'll take a look, but caveat: I know "not a lot" about mdb or using DataSet in anger. – Twophase

Answer 2

as mentioned DataAdapters are one of the easy ways.

See: http://www.codeproject.com/KB/database/relationaladonet.aspx

for a pretty simple example that I think covers what youu need.

Funchal

Answer 3

With dataTable.GetChanges() you can get changes as a list. Iterating through them you can apply insert/update/delete operations. Here is a sample save button saving the changes to oracle db from DataGridView.

I implemented insert and update. You can simply implement delete too. Also note that I assumed the tables has first column as primary key for simplicity. You can alter the code to use it for multiple column pks. Table is dynamically selected from a ComboBox.

private void button_SaveToDb_Click(object sender, EventArgs e)
    {
        using (OracleConnection conn = new OracleConnection())
        {
            conn.ConnectionString = textBox_ConString.Text;
            conn.Open();
            var dataTable = (DataTable)dataGridView1.DataSource;
            var changes = dataTable.GetChanges();
            if (changes != null)
            {
                foreach (DataRow row in changes.Rows)
                {
                    switch (row.RowState)
                    {
                        case DataRowState.Added:
                            OracleCommand command = new OracleCommand()
                            {
                                Connection = conn,
                                BindByName = true
                            };
                            var qry = $"INSERT INTO {comboBox_Tables.SelectedItem.ToString()} (";
                            StringBuilder sb = new StringBuilder();
                            int i = 0;
                            foreach (var col in row.Table.Columns)
                            {
                                sb.Append(col + ((i == row.Table.Columns.Count - 1) ? "" : ","));
                                command.Parameters.Add(new OracleParameter(col.ToString(), row.ItemArray[i]));
                                i = i + 1;
                            }
                            sb.Append(") VALUES (");
                            i = 0;
                            foreach (var col in row.Table.Columns)
                            {
                                sb.Append(":" + col + ((i == row.Table.Columns.Count - 1) ? "" : ","));
                                command.Parameters.Add(new OracleParameter(col.ToString(), row.ItemArray[i]));
                                i = i + 1;
                            }
                            sb.Append(")");
                            command.CommandText = qry + sb;
                            command.ExecuteNonQuery();
                            break;
                        case DataRowState.Deleted:
                            break;
                        case DataRowState.Modified:
                            command = new OracleCommand()
                            {
                                Connection = conn,
                                BindByName = true
                            };
                            qry = $"UPDATE {comboBox_Tables.SelectedItem.ToString()} SET ";
                            sb = new StringBuilder();
                            i = 0;
                            foreach (var col in row.Table.Columns)
                            {
                                if (i > 0)
                                {
                                    sb.Append(col + "=:" + col + ((i == row.Table.Columns.Count - 1) ? "" : ","));
                                }

                                command.Parameters.Add(new OracleParameter(col.ToString(), row.ItemArray[i]));
                                i = i + 1;
                            }
                            command.CommandText = qry + sb + $" WHERE {row.Table.Columns[0]} = :{row.Table.Columns[0]}";
                            command.ExecuteNonQuery();
                            break;
                    }
                }

                ((DataTable)dataGridView1.DataSource).AcceptChanges();
            }
        }
    }

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