改变DataGrid某一行和单元格的颜色

前段时间做WPF项目，需要改变DataGrid某一行的颜色、高度，以及某个单元格的颜色、单元格字体的颜色，自然就必需取到datagrid的一行和一行的单元格，网上也是搜索了好久才找到，记录下来便于使用。

1、前台WPF界面添加一个DataGrid控件，并添加两列（便于编写，达到目的即可）

<DataGrid AutoGenerateColumns="False" Height="642" HorizontalAlignment="Left" Margin="131,57,0,0" Name="dataGrid1" VerticalAlignment="Top" Width="799" CanUserAddRows="True" LoadingRow="dataGrid1_LoadingRow" GridLinesVisibility="None">
            <DataGrid.ColumnHeaderStyle >
                <Style TargetType="DataGridColumnHeader">
                    <Setter Property="Height" Value="50"></Setter>
                </Style>
            </DataGrid.ColumnHeaderStyle>
            <DataGrid.Columns>
                <DataGridTextColumn Header="id" Binding="{Binding Path=id}" ElementStyle="{StaticResource dgCell}"></DataGridTextColumn>
                <DataGridTextColumn Header="name" Binding="{Binding Path=name}" ElementStyle="{StaticResource dgCell}"></DataGridTextColumn>
            </DataGrid.Columns>
        </DataGrid>

2、创建一个数据源并绑定，此处是创建一个datatable

DataTable dt = new DataTable();
            dt.Columns.Add(new DataColumn("id", typeof(int)));
            dt.Columns.Add(new DataColumn("name", typeof(string)));

            for (int i = 0; i < 6; i++)
            {
                DataRow dr = dt.NewRow();
                if (i == 3)
                {
                    dr["id"] = DBNull.Value;
                    dr["name"] = DBNull .Value ;
                    dt.Rows.Add(dr);
                }
                else
                {
                    dr["id"] = i;
                    dr["name"] = "tom" + i.ToString();
                    dt.Rows.Add(dr);
                }
            }

            this.dataGrid1.CanUserAddRows = false;
            this.dataGrid1.ItemsSource = dt.DefaultView;

3、获取单行

for (int i = 0; i < this.dataGrid1.Items.Count; i++)
            {
                DataRowView drv = dataGrid1.Items[i] as DataRowView;
                DataGridRow row = (DataGridRow)this.dataGrid1.ItemContainerGenerator.ContainerFromIndex(i);

                if (i == 2)
                {
                    row.Height = 50;
                    row.Background = new SolidColorBrush(Colors.Blue);
                    drv["id"] = 333;
                }

                if (drv["id"] == DBNull.Value)
                {
                    row.Background = new SolidColorBrush(Colors.Green);
                    row.Height = 8;
                }
            }

4、获取单元格

for (int i = 0; i < this.dataGrid1.Items.Count; i++)
            {
                DataRowView drv = dataGrid1.Items[i] as DataRowView;
                DataGridRow row = (DataGridRow)this.dataGrid1.ItemContainerGenerator.ContainerFromIndex(i);if (i == 4)
                {
                    DataGridCellsPresenter presenter = GetVisualChild<DataGridCellsPresenter>(row);
                    DataGridCell cell = (DataGridCell)presenter.ItemContainerGenerator.ContainerFromIndex(1);
                    cell.Background = new SolidColorBrush(Colors.Red);
                }
            }

public static T GetVisualChild<T>(Visual parent) where T : Visual
        {
            T childContent = default(T);
            int numVisuals = VisualTreeHelper.GetChildrenCount(parent);
            for (int i = 0; i < numVisuals; i++)
            {
                Visual v = (Visual)VisualTreeHelper.GetChild(parent, i);
                childContent = v as T;
                if (childContent == null)
                {
                    childContent = GetVisualChild<T>(v);
                }
                if (childContent != null)
                {
                    break;
                }
            }

            return childContent;
        }

5、如果在项目中把创建数据源、绑定数据源、对datagrid进行操作（改变行的颜色、高度）都写在一个事件中，其中在取datagrid的row时出现错误：未将对象引用设置到对象的实例。

解决的方法：

   //创建数据源、绑定数据源

 if (!Window.GetWindow(dataGrid1).IsVisible)
            {
                Window.GetWindow(dataGrid1).Show();
            }
            dataGrid1.UpdateLayout();

//可以获取某一行、某一行的单元格