1

我有一个数据绑定到 BindingList 的 DataGridView

private void InitGrid()
{
    Ctx.MyEntitySet.Load();
    dataGridView1.DataSource = Ctx.MyEntitySet.Local.ToBindingList();
    dataGridView1.Columns["Id"].Visible = false;
    dataGridView1.Columns["UnwantedCol1"].Visible = false;
    dataGridView1.Columns["UnwantedCol2"].Visible = false;
    dataGridView1.Columns["UnwantedCol3"].Visible = false;
}

和一个过滤文本框，一个 TextChanged 事件像这样处理

private void textBoxFilter_TextChanged(object sender, EventArgs e)
{
    try
    {
        string filter = textBoxFilter.Text.Trim();
        ((DataView)dataGridView1.DataSource).RowFilter = filter;
        textBoxFilter.BackColor = SystemColors.AppWorkspace;
    }
    catch (Exception)
    {
        textBoxFilter.BackColor = Color.Red;
        ToolTip tip = new ToolTip();
        tip.SetToolTip(textBoxFilter, ex.Message);
    }
}

我运行代码，数据正确显示，但是当我尝试ColumnName like '%sometext%'在我的过滤器文本框中键入类似的内容时，我收到一个异常，说我无法投射'System.Data.Entity.Internal.ObservableBackedBindingList`1[MyEntity] ' 到 'System.Data.DataView'。

谁能给我指点？

谢谢，F。

解决：

添加了通用扩展方法

public static class LocalExtensions
{
    public static IEnumerable<T> Filter<T>(this IEnumerable<T> list, Func<T, bool> filterParam)
    {
        return list.Where(filterParam);
    }
}

并像这样修改了 TextChanged 事件处理程序：

private void textBoxFilter_TextChanged(object sender, EventArgs e)
{
    try
    {
        string filter = textBoxFilter.Text.Trim();

        dataGridView1.DataSource =
            Ctx.MyEntitySet.Local
            .Filter(x =>
                x.EntityPropertyToSearchIn1.ToUpper().Contains(filter.ToUpper()) ||
                x.EntityPropertyToSearchIn2.ToUpper().Contains(filter.ToUpper())
            ).ToList();

        textBoxFilter.BackColor = SystemColors.AppWorkspace;
    }
    catch (Exception)
    {
        textBoxFilter.BackColor = Color.Red;
        ToolTip tip = new ToolTip();
        tip.SetToolTip(textBoxFilter, ex.Message);
    }
}
4

3 回答 3

1

And here is the VB equivalent for the extension method:

Imports System.Runtime.CompilerServices

Module LocalExtensions

    <Extension()> _
    Public Function Filter(Of T)(list As IEnumerable(Of T), filterParam As Func(Of T, Boolean)) As IEnumerable(Of T)
        Return list.Where(filterParam)
    End Function

End Module
于 2015-01-29T15:09:34.357 回答
1

基本上，您不能将BindingList直接放入 DataGridView。您需要定义一个BindingSource并将 BindingList 分配给此 BindingSource。试试这个看看它是否有效：

Ctx.MyEntitySet.Load();
BindingSource yourBS = new BindingSource();
yourBS.DataSource = Ctx.MyEntitySet.Local.ToBindingList();

dataGridView1.DataSource = yourBS;
dataGridView1.Columns["Id"].Visible = false;
dataGridView1.Columns["UnwantedCol1"].Visible = false;
dataGridView1.Columns["UnwantedCol2"].Visible = false;
dataGridView1.Columns["UnwantedCol3"].Visible = false;

我希望它有效。:)

问候。

于 2012-10-31T10:49:19.793 回答
1

You would have to create a new BindingList that is filtered. Easy to do with LINQ. See Filtering a Binding List

try
{
    string filter = textBoxFilter.Text.Trim();
    dataGridView1.DataSource = new BindingList<YOUR_ENTITY>(Ctx.MyEntitySet.Local.ToBindingList().Where(x => x.EntityPropertyToSearchIn1.ToUpper().Contains(filter)).ToList<YOUR_ENTITY>());
    textBoxFilter.BackColor = SystemColors.AppWorkspace;
}
于 2014-04-08T22:25:42.987 回答