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using System;
using MySql.Data.MySqlClient;
using System.Data;

namespace database
{
	/// <summary>
	/// Description of DbOp.
	/// </summary>
	public class DbOp
	{
		private string table;
		private MySqlConnection con;
		private string login = 
				"SERVER=localhost;" +
				"DATABASE=test;" +
				"UID=root;" +
				"Password=;";
		private MySqlDataAdapter adapter;
		private string opString = "select * from test";
		
		public DbOp(string table_name)
		{
			table = table_name;
			con = new MySqlConnection(login);
			adapter = new MySqlDataAdapter(opString, con);
			initCommands();
		}
		public void Fill(ref DataTable tabelle)
		{
			adapter.Fill(tabelle);
		}
		public void Update(ref DataTable tabelle)
		{
			adapter.Update(tabelle);
			
		}
		private void initCommands()
		{
			adapter.InsertCommand = new MySqlCommand("Insert into test(id, name) values(@id, @name)", con);
			adapter.InsertCommand.Parameters.Add("@id", MySqlDbType.Int32);
			adapter.InsertCommand.Parameters.Add("@name", MySqlDbType.Text, 65535, "name");
		}
		
	}
}

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using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
using MySql.Data.MySqlClient;
using System.Data;


namespace database
{
	/// <summary>
	/// Description of MainForm.
	/// </summary>
	public partial class MainForm : Form
	{
		DbOp operation;
		DataTable tabelle = new DataTable();
		public MainForm()
		{
			//
			// The InitializeComponent() call is required for Windows Forms designer support.
			//
			InitializeComponent();
			
			//
			// TODO: Add constructor code after the InitializeComponent() call.
			//
			operation = new DbOp("test");
			operation.Fill(ref tabelle);
			dataGridView1.DataSource = tabelle;
			dataGridView1.Columns["id"].ReadOnly = true;
		}
		
		void DataGridView1UserAddedRow(object sender, DataGridViewRowEventArgs e)
		{
			
		}
		
		void DataGridView1CellEndEdit(object sender, DataGridViewCellEventArgs e)
		{
			operation.Update(ref tabelle);
		}
	}
}

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dataGridView1.Rows[dataGridView1.CurrentRow.Index].Cells["name"].Value.ToString()

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dataGridView1.Rows[dataGridView1.CurrentRow.Index].Cells["name"].Value.ToString()

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************** Exception Text **************
System.NullReferenceException: Object reference not set to an instance of an object.
   at database.MainForm.DataGridView1CellValueChanged(Object sender, DataGridViewCellEventArgs e) in c:\Users\Jakob\Documents\SharpDevelop Projects\database\database\MainForm.cs:line 56
   at System.Windows.Forms.DataGridView.OnCellValueChanged(DataGridViewCellEventArgs e)
   at System.Windows.Forms.DataGridView.OnCellValueChangedInternal(DataGridViewCellEventArgs e)
   at System.Windows.Forms.DataGridViewCell.SetValue(Int32 rowIndex, Object value)
   at System.Windows.Forms.DataGridView.PushFormattedValue(DataGridViewCell& dataGridViewCurrentCell, Object formattedValue, Exception& exception)
   at System.Windows.Forms.DataGridView.CommitEdit(DataGridViewCell& dataGridViewCurrentCell, DataGridViewDataErrorContexts context, DataGridViewValidateCellInternal validateCell, Boolean fireCellLeave, Boolean fireCellEnter, Boolean fireRowLeave, Boolean fireRowEnter, Boolean fireLeave)
   at System.Windows.Forms.DataGridView.EndEdit(DataGridViewDataErrorContexts context, DataGridViewValidateCellInternal validateCell, Boolean fireCellLeave, Boolean fireCellEnter, Boolean fireRowLeave, Boolean fireRowEnter, Boolean fireLeave, Boolean keepFocus, Boolean resetCurrentCell, Boolean resetAnchorCell)
   at System.Windows.Forms.DataGridView.CommitEditForOperation(Int32 columnIndex, Int32 rowIndex, Boolean forCurrentCellChange)
   at System.Windows.Forms.DataGridView.ScrollIntoView(Int32 columnIndex, Int32 rowIndex, Boolean forCurrentCellChange)
   at System.Windows.Forms.DataGridView.ProcessDownKeyInternal(Keys keyData, Boolean& moved)
   at System.Windows.Forms.DataGridView.ProcessEnterKey(Keys keyData)
   at System.Windows.Forms.DataGridView.ProcessDialogKey(Keys keyData)
   at System.Windows.Forms.Control.ProcessDialogKey(Keys keyData)
   at System.Windows.Forms.TextBoxBase.ProcessDialogKey(Keys keyData)
   at System.Windows.Forms.Control.PreProcessMessage(Message& msg)
   at System.Windows.Forms.Control.PreProcessControlMessageInternal(Control target, Message& msg)
   at System.Windows.Forms.Application.ThreadContext.PreTranslateMessage(MSG& msg)

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dataGridView1.Rows[dataGridView1.Rows.Count-1].Cells["name"].Value.ToString()

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         MySqlConnection con = new MySqlConnection(login);
         MySqlDataAdapter adapter = new MySqlDataAdapter(opString, con);

         //damit DataTable INSERT, UPDATE, DELETE Statements richtig behandelt
         MySqlCommandBuilder cb = new MySqlCommandBuilder(adapter, true);

         tabelle = "deine änderungen";
         DataTable changes = tabelle.getChanges();
         adapter.Update (changes);
         tabelle.AcceptChanges();