Proprietà DataGridTableStyle.PreferredColumnWidth

private void CreateAndBindDataSet(DataGrid myDataGrid)
{
   DataSet myDataSet = new DataSet("myDataSet");
   DataTable myEmpTable = new DataTable("Employee");
   // Create two columns, and add them to employee table.
   DataColumn myEmpID = new DataColumn("EmpID", typeof(int));
   DataColumn myEmpName = new DataColumn("EmpName");
   myEmpTable.Columns.Add(myEmpID);
   myEmpTable.Columns.Add(myEmpName);
   // Add table to DataSet.
   myDataSet.Tables.Add(myEmpTable);
   // Populate table.
   DataRow newRow1;
   // Create employee records in employee Table.
   for(int i = 1; i < 6; i++)
   {
      newRow1 = myEmpTable.NewRow();
      newRow1["EmpID"] = i;
      // Add row to Employee table.
      myEmpTable.Rows.Add(newRow1);
   }
   // Give each employee a distinct name.
   myEmpTable.Rows[0]["EmpName"] = "Alpha";
   myEmpTable.Rows[1]["EmpName"] = "Beta";
   myEmpTable.Rows[2]["EmpName"] = "Omega";
   myEmpTable.Rows[3]["EmpName"] = "Gamma";
   myEmpTable.Rows[4]["EmpName"] = "Delta";
   // Bind DataGrid to DataSet.
   myDataGrid.SetDataBinding(myDataSet, "Employee");
}

private void Form1_Load(object sender, System.EventArgs e)
{
   // Set and Display myDataGrid.
   myDataGrid.DataMember = "";
   myDataGrid.Location = new System.Drawing.Point(72, 32);
   myDataGrid.Name = "myDataGrid";
   myDataGrid.Size = new System.Drawing.Size(240, 200);
   myDataGrid.TabIndex = 4;
   // Add it to controls.
   Controls.Add(myDataGrid);
   CreateAndBindDataSet(myDataGrid);
   myDataGridTableStyle.MappingName = "Employee";
   // Set other properties.
   myDataGridTableStyle.AlternatingBackColor = Color.LightGray;
   // Add DataGridTableStyle instances to GridTableStylesCollection.
   myDataGridTableStyle.PreferredColumnWidth = 100;
   myColWidth.Text = "";
   myDataGrid.TableStyles.Add(myDataGridTableStyle);
   myDataGridTableStyle.PreferredColumnWidthChanged +=
         new EventHandler(MyDelegatePreferredColWidthChanged);
}

private void MyDelegatePreferredColWidthChanged(object sender, EventArgs e)
{
   MessageBox.Show("Preferred Column width has changed");
}

private void myButton_Click(object sender, System.EventArgs e)
{
   try
   {
      if( myColWidth.Text != "" )
      {
         int newwidth = myDataGridTableStyle.PreferredColumnWidth = 
            int.Parse(myColWidth.Text);
         // Dispose datagrid and datagridtablestyle and then create.
         myDataGrid.Dispose();
         myDataGridTableStyle.Dispose();
         myDataGrid = new DataGrid();
         myDataGridTableStyle = new DataGridTableStyle();
         myDataGrid.DataMember = "";
         myDataGrid.Location = new System.Drawing.Point(72, 32);
         myDataGrid.Name = "myDataGrid";
         myDataGrid.Size = new System.Drawing.Size(240, 200);
         myDataGrid.TabIndex = 4;
         Controls.Add(myDataGrid);
         CreateAndBindDataSet(myDataGrid);
         myDataGridTableStyle.MappingName = "Employee";
         // Set other properties.
         myDataGridTableStyle.AlternatingBackColor = Color.LightGray;
         // Add DataGridTableStyle instances to GridTableStylesCollection.
         myDataGridTableStyle.PreferredColumnWidth = newwidth;
         myColWidth.Text = "";
         myDataGrid.TableStyles.Add(myDataGridTableStyle);
         myDataGridTableStyle.PreferredColumnWidthChanged += 
            new EventHandler(MyDelegatePreferredColWidthChanged);
      }
      else
      {
         MessageBox.Show("Please enter a number");
      }
   }
   catch(Exception ex)
   {
      MessageBox.Show(ex.Message);
   }
}