如何将selectedItems放在列表的顶部？ [英] How to get the selectedItems on top of the list?

问题描述

Hello Experts，



我有一个Windows窗体。我必须创建一个多选项，就像检查下拉列表一样。我想在选中后将所选项目置于顶部。并清除列表的其余部分。可能吗？我不知道如何做到这一点。

这是我的Checkeddropdown列表数据源的代码

Hello Experts,

I have a windows forms. I have to create a multiple selection which is like checked dropdownlist. I want to get the selected Items on the top once it is selected. And clear the rest of the list. Is it possible? I don't have idea about how to do this.
Here is my code for Checkeddropdown list Datasource

Dim dsclass As DataSet = dbDev.GetClass()
   CheckedListBox1.DataSource = dsclass.Tables(0)
   CheckedListBox1.DisplayMember = "RMCCLS"
   CheckedListBox1.ValueMember = "RMCCLS"

之后我检查下拉列表中的方框，我需要将所选项目放在最上面。



如果这个想法不好而且不友好。你可以分享一下这样的想法吗？

After I check the boxes in the drop down list, I need to get the selected items on Top.

If the idea is bad and not amicable. Could you please share any such ideas?

推荐答案

如果您可以删除不仅显示的行而且还可以删除原始DataTable中的行，请执行以下操作：

If it's ok for you to remove the rows not only from being displayed but also from the original DataTable, then do this:

// get the DataTable "back":
DataTable dataTable = ((DataView)CheckedListBox1.DataSource).Table;

// the selected Rows are "in" .CheckedItems in form of DataRowViews:
IEnumerable<DataRow> selectedRows = CheckedListBox1.CheckedItems.Cast<DataRowView>().Select(x => x.Row);

// create a HashSet of the selected DataRows for fast lookup:
HashSet<DataRow> selectedRowsHashset = new HashSet<DataRow>(selectedRows);

// loop over the DataRows in the DataTable in reverse order:
// (required because we're going to remove DataRows)
for (int rowIndex = dataTable.Rows.Count - 1; rowIndex >= 0; rowIndex--)
{
    // remove the DataRow at rowIndex if it is not among the selected rows:
    if (!selectedRowsHashset.Contains(dataTable.Rows[rowIndex]))
    {
        dataTable.Rows.RemoveAt(rowIndex);
    }
}

如果您只想显示删除的行，请执行以下操作：

If you only want the rows removed from being displayed, then do this:

// get the DataTable "back":
DataTable sourceDataTable = ((DataView)CheckedListBox1.DataSource).Table;

// create a structural clone:
DataTable newDataTable = sourceDataTable.Clone();

// loop over the selected DataRows:
foreach (DataRow sourceRow in CheckedListBox1.CheckedItems.Cast<DataRowView>().Select(x => x.Row))
{
    // create a new DataRow and copy the values of the selected DataRow:
    DataRow newRow = newDataTable.NewRow();
    for (int columnIndex = 0; columnIndex < newDataTable.Columns.Count; columnIndex++)
    {
        newRow[columnIndex] = sourceRow[columnIndex];
    }
    // add the DataRow-copy to the new DataTable:
    newDataTable.Rows.Add(newRow);
}

// set the new DataTable as new DataSource for the CheckedListBox:
CheckedListBox1.DataSource = newDataTable;

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