具有運行時列的DataGridView

Question

我正在使用C＃，Windows Forms，.NET 3.5 SP1

我有一個DataGridView，其中包含很多直到運行時才知道的列（即，我不知道直到運行時才需要Foo列）。 為了使數據進出單元，我正在考慮以下架構。

我是在正確的軌道上，還是我缺少一些輕松的事情？

public interface ICustomColumn
{
    object Format (DataGridView dgv, DataGridViewCellFormattingEventArgs e);
    void Validate (DataGridView dgv, DataGridViewCellValidatingEventArgs e);
}

public class CustomDataGridView : DataGridView 
{
    protected override void OnCellFormatting (DataGridViewCellFormattingEventArgs e)
    {
        ICustomColumn col = Columns [e.ColumnIndex].Tag as ICustomColumn;
        if ( col != null )
            e.Value = col.Format (this, e);

        base.OnCellFormatting (e);
    }

    protected override void OnCellValidating (DataGridViewCellValidatingEventArgs e)
    {
        ICustomColumn col = Columns [e.ColumnIndex].Tag as ICustomColumn;
        if ( col != null )
            col.Validate (this, e);

        base.OnCellValidating (e);
    }
}

class FooColumn : ICustomColumn
{
    public FooColumn (Dictionary <RowData, Foo> fooDictionary) 
        { this.FooDictionary = fooDictionary; }

    // Foo has a meaningful conversion to the column type (e.g. ToString () for a text column
    protected object Format (DGV dgv, DGVCFEA e)
        { return FooDictionary [(RowData) dgv.Rows[e.RowIndex].DataBoundItem]; }

    // Foo has a meaningful way to interpret e.FormattedValue
    void Validate (DGV dgv, DGVCVEA e)
        { FooDictionary [(RowData) dgv.Rows[e.RowIndex].DataBoundItem].Validate (e.FormattedValue); }
}

void CreateFooColumn (DataGridView dgv)
{
    dgv.Columns.Add (new DataGridViewTextBoxColumn () { Tag = new FooColumn (fooDictionary) });
}

Answer 1

另一種方法是使用反射。

設置DataGridView：

private void SetUpDataGridView()
{
    // Create the columns based on the data in the album info - get by reflection
    var ai = new AlbumInfo();
    Type t = ai.GetType();

    dataTable.TableName = t.Name;

    foreach (PropertyInfo p in t.GetProperties())
    {
        var columnSpec = new DataColumn();
        // If nullable get the underlying type
        Type propertyType = p.PropertyType;
        if (IsNullableType(propertyType))
        {
            var nc = new NullableConverter(propertyType);
            propertyType = nc.UnderlyingType;
        }
        columnSpec.DataType = propertyType;
        columnSpec.ColumnName = p.Name;
        dataTable.Columns.Add(columnSpec);
    }
}

輔助方法：

private bool IsNullableType(Type theType)
{
    return (theType.IsGenericType &&
            theType.GetGenericTypeDefinition().Equals(typeof(Nullable<>)));
}

要填充DataGridView：

private void AddToGrid(AlbumInfo info)
{
    // Add album info to table - add by reflection
    Type t = info.GetType();
    var row = new object[t.GetProperties().Length];

    int index = 0;
    foreach (PropertyInfo p in t.GetProperties())
    {
        row[index++] = p.GetValue(info, null);
    }

    dataTable.Rows.Add(row);
    dataGridView.ClearSelection();
}