WPF 遍历数据网格

Question

Using WPF C#.NET4.5 using visual studio 2012 ulti.

Old winforms code:

foreach (DataGridViewRow paretoRow in ParetoGrid.Rows)
{
       if ((Convert.ToInt32(paretoRow.Cells["CurrentPareto"].Value) < (Convert.ToInt32(paretoRow.Cells["NewPareto"].Value))))
       {
              paretoRow.Cells["pNew"].Value = downArrow
       }
}

As you can see each row I cycle through I check a specific cell, if true I then populate another cell. This was good old winforms code I used many times before...however. Switching over to WPF was alot more different than i previously assumed.

DataGrid does not contain the Row property. Instead, I think you need to use:

DataGridRow paretoRow in paretogrid.Items

But im still at a loss on who to now get the cell.

So my question is, is there syntax changes to perform, if so where? Or as I'm beginning to believe datagrids in WPF operate with Objects more so than winforms thus not needing to use a propertie called "row", if this is the case what logic/syntax should i know use in this example?

Thanks for your patience guys, think when I go home for the bank holiday I'll do a bit of WPF digging to see how different it actually is.

Answer 1

I think first think you want to do is to get all rows of your DataGrid :

public IEnumerable<Microsoft.Windows.Controls.DataGridRow> GetDataGridRows(Microsoft.Windows.Controls.DataGrid grid)
{
    var itemsSource = grid.ItemsSource as IEnumerable;
    if (null == itemsSource) yield return null;
    foreach (var item in itemsSource)
    {
        var row = grid.ItemContainerGenerator.ContainerFromItem(item) as Microsoft.Windows.Controls.DataGridRow;
        if (null != row) yield return row;
    }
}

and then iterate through your grid:

var rows = GetDataGridRows(nameofyordatagrid); 

foreach (DataGridRow row in rows)  
{  
  DataRowView rowView = (DataRowView)row.Item;
  foreach (DataGridColumn column in nameofyordatagrid.Columns)
  {
      if (column.GetCellContent(row) is TextBlock)
      {
          TextBlock cellContent = column.GetCellContent(row) as TextBlock;
          MessageBox.Show(cellContent.Text);
      }
  } 

Answer 2

People seem to be overcomplicating this, this worked for me:

foreach (System.Data.DataRowView dr in yourDataGrid.ItemsSource)
{
     MessageBox.Show(dr[0].ToString());
}

Answer 3

Yes, you are right. WPF DataGrid is built around better supporting the use of objects.

You could use a ViewModel similar to the following. Build them all into a collection and then set that collection as your ItemsSource . You would also need to use a ValueConverter if you want to display and image instead of a checkmark for pNew being true/false.

public class FooViewModel : INotifyPropertyChanged
{
    private int currentPareto;
    public int CurrentPareto 
    {
        get
        {
           return currentPareto;
        }
        set
        { 
            if (currentPareto == value)
                return;

            currentPareto = value;
            OnPropertyChanged("CurrentPareto");
            OnPropertyChanged("pNew");
        }
    }

    private int newPareto;
    public int NewPareto 
    {
        get
        {
           return newPareto;
        }
        set
        { 
            if (newPareto == value)
                return;

            newPareto = value;
            OnPropertyChanged("NewPareto");
            OnPropertyChanged("pNew");
        }
    }

    public bool pNew
    {
        get
        {
            return CurrentPareto < NewPareto;
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    public void OnPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

Edit

To simplify it a little, you could use a base ViewModel class and use PropertyChanged weaving. The code would simplify to this:

public class FooViewModel : ViewModelBase
{
    public int CurrentPareto { get; set; }
    public int NewPareto { get; set; }
    public bool pNew { get { return CurrentPareto < NewPareto; } }
}

Answer 4

The 'simplest' answer, from Charles, did it for me. But I used Items instead of ItemsSource .

Now, for people getting this error:

System.InvalidCastException
Unable to cast object of type 'MS.Internal.NamedObject' to type 'System.Data.DataRowView'.

What did it for me was disabling the DataGrid's property CanUserAddRows . This removes the placeholder line for a new line, thus removing the placeholder object (which is NOT a DataRowView, but something else). If you already have this disabled, then I don't know.

Since I wanted to loop through each element of each row, I added another foreach :

foreach (System.Data.DataRowView dr in nameofyourgrid.Items)
{
    foreach (var item in dr.Row.ItemArray)
    {
        MessageBox.Show(item.ToString());
    }
}

Answer 5

In WPF you go about it a lot more dynamic and ObjectOrientated. You can bind the Column "pNew" on a Property of the element you put in the DataGrid , which returns downarrow. If the value changes you can raise the Event PropertyChanged (Interface INotifyPropertyChanged ) and the bound Property will get reevaluated.

Also interesting for beginning with WPF is DataTemplate , ControlTemplate , Converter . Converter changes the Property Value to a usable Value for WPF (eg BoolToVisibility) when the Property gets called. DataTemplate and ControlTemplate can be used to alter the appearance of the Control.

There are several good Tutorials for WPF out there. I would also recommend to look into the MVVM-Pattern to use as a between layer of your Businessobject and your WPF-Control, especially to handle things like what you try to do here.

Answer 6

I don't even understand why is it just so complicated to get rows and their values in a datagrid. It feels like hell finding how. The api even give funny funny event names which is not so direct to the point also. Why can't just people concentrate on the baseline and give what exactly is needed and not all sorts of different options with no use and sense at all. I mean to eat all you need is a spoon and fork right. Never even changed since 100,000 years ago. This is my code thanks to the guy who mentioned some people just try to over-complicate things and waste your time.

    private void dtaResultGrid_DataContextChanged(object sender, DependencyPropertyChangedEventArgs e)
    {
        ActivateTestDatagridAccess();
    }

    public async void ActivateTestDatagridAccess()
    {
        try
        {
            await Task.Delay(500);
            foreach (System.Data.DataRowView dr in dtaResultGrid.ItemsSource)
            {
                for (int j = 0; j < dtaResultGrid.Columns.Count; j++)
                {
                    Console.WriteLine(dr[j].ToString());
                }
                Console.Write(Environment.NewLine);
            }
        }
        catch (Exception exrr)
        {
            Console.WriteLine(exrr.ToString());
        }
    }

Answer 7

if you fill your datagridview rows using an instance of a class (like struct_class) this would be the fastest way to have a foreach loop

foreach (struct_class row in dgv.Items)
{
    MessageBox.Show(row.name);
}

Answer 8

为什么你不能只使用这个属性来获取行数，然后使用For循环来迭代？

dataGridView1.Rows.Count