如何根据第一个 GridViewComboBoxColumn 的选择填充第二个列

Question

我有两个 DataGridViewComboBoxColumn。我想根据第一个 GridViewComboBoxColumn 的选择填充第二列。我在第一个 Combobox 中有组，在第二个 Combobox 中有服务。我希望当我选择 group1 时，只有 group1 的服务显示在服务组合框中。 我正在使用存储过程。

var groupColumn = new DataGridViewComboBoxColumn();

                DataTable dtcategori = cb.GetAllDataCategori();
                groupColumn.Name = "Group";
                groupColumn.HeaderText = Resources.GroupName;
                groupColumn.DataSource = dtcategori;
                groupColumn.ValueMember = "ID";
                groupColumn.DisplayMember = "Name";
                groupColumn.Width = 100;
                this.DataGridViewFactor.Columns.Add(groupColumn);

                var serviceColumn = new DataGridViewComboBoxColumn();
                    //var categoriId = Convert.ToInt32(groupColumn.);
                // DataTable dtServices = sb.ServiceGetById(categoriId);
                    DataTable dtServices = sb.GetAllDataServices();
                    serviceColumn.Name = "Services";
                    serviceColumn.HeaderText = Resources.Service;
                    serviceColumn.DataSource = dtServices;
                    serviceColumn.ValueMember = "ID";
                    serviceColumn.DisplayMember = "Name";
                    serviceColumn.Width = 100;

                    this.DataGridViewFactor.Columns.Add(serviceColumn);

Answer 1

哇，我花了大约 2 个小时才找到这个答案，虽然不好但有用且有帮助:)

首先，您必须将 groupColumn.DataSource 更改为 BindingSource 而不是代码中的 DataTable，因为当您从 groupColumn 的组合框中选择项目时，您需要一些 PositionChanged 事件来通知.你知道DataGridViewColumn 没有任何SelectedIndexChanged 事件。其次，我看不出你的Group 和Services 之间有什么关系，Services 的数据源应该有一个类似GroupID 的字段，这样你就可以在两列之间链接。我想有这样一个GroupID 字段。你的Services 有一个ID，但我不确定是不是GroupID，可能是你的ServiceID。

推荐：我认为您应该将您的 groupColumn's 和 serviceColumn's DisplayStyle 更改为 DataGridViewComboBoxDisplayStyle.Nothing - 我觉得最好。

我想在代码旁边的评论中解释我的解决方案。代码如下：

//Your code is modified a little.
var groupColumn = new DataGridViewComboBoxColumn();
groupColumn.DisplayStyle = DataGridViewComboBoxDisplayStyle.Nothing;
DataTable dtcategori = cb.GetAllDataCategori();
groupColumn.Name = "Group";
groupColumn.HeaderText = Resources.GroupName;
//Create a BindingSource from your DataTable
BindingSource bs = new BindingSource(dtcategori,"");
groupColumn.DataSource = bs;
bs.PositionChanged += (s,e) => {
   //Filter for items which have the selected GroupID
   ((DataTable)((DataGridViewComboBoxColumn)DataGridViewFactor.Columns["Services"]).DataSource).DefaultView.RowFilter =
                string.Format("GroupID='{0}'",((DataRowView)bs.Current).Row["ID"]);
   //Set the initial value of the corresponding cell in serviceColumn
   DataGridViewFactor.CurrentRow.Cells["Services"].Value = ((DataTable)((DataGridViewComboBoxColumn)DataGridViewFactor.Columns["Services"]).DataSource).DefaultView.ToTable().Rows[0]["Name"];
};
//-------------------------------------------
groupColumn.ValueMember = "ID";
groupColumn.DisplayMember = "Name";
groupColumn.Width = 100;
this.DataGridViewFactor.Columns.Add(groupColumn);

var serviceColumn = new DataGridViewComboBoxColumn();
serviceColumn.DisplayStyle = DataGridViewComboBoxDisplayStyle.Nothing;
//var categoriId = Convert.ToInt32(groupColumn.);
// DataTable dtServices = sb.ServiceGetById(categoriId);
DataTable dtServices = sb.GetAllDataServices();
serviceColumn.Name = "Services";
serviceColumn.HeaderText = Resources.Service;
serviceColumn.DataSource = dtServices;
serviceColumn.ValueMember = "ID";
serviceColumn.DisplayMember = "Name";
serviceColumn.Width = 100;

this.DataGridViewFactor.Columns.Add(serviceColumn);

//Because filtering this way can make some cell have a value which is not contained in 
//the DataGridViewComboBoxColumn.Items, we have to handle the DataError
private void DataGridViewFactor_DataError(object sender, DataGridViewDataErrorEventArgs e){
    //We're interested only in DataGridViewComboBoxColumn
    if(DataGridViewFactor.Columns[e.ColumnIndex] is DataGridViewComboBoxColumn){
        e.Cancel = true;
    }
}
//Because when you filter on a row, the DataGridViewComboBoxColumn.DataSource with
//the filtered DefaultView will apply on all the rows in the same 
//DataGridViewComboBoxColumn, we have to apply the filter for each row if it is selected
private void DataGridViewFactor_SelectionChanged(object sender, EventArgs e)
{            
        ((DataTable)((DataGridViewComboBoxColumn)DataGridViewFactor.Columns["Services"]).DataSource).DefaultView.RowFilter =
           string.Format("GroupID='{0}'", DataGridViewFactor.CurrentRow.Cells["Group"].Value);            
}
//Because when you filter on a row, the DataSource DefaultView of the groupColumn will
//be changed (limited to fewer items) and there will be cells in that column having 
//values which are not contained in the filtered items. Those cells will not be 
//displayed when you move the mouse over. This CellPainting event handler is to help 
//them look normal.
private void DataGridViewFactor_CellPainting(object sender, DataGridViewCellPaintingEventArgs e){
    if (e.RowIndex > -1 && e.ColumnIndex > -1)
    {
            if (e.Value != null)
            {
                e.Handled = true;
                e.PaintBackground(e.CellBounds, true);
                StringFormat sf = new StringFormat() { LineAlignment = StringAlignment.Center };
                e.Graphics.DrawString(e.Value.ToString(), DataGridViewFactor.Font, new SolidBrush(DataGridViewFactor.ForeColor), e.CellBounds, sf);
            }
    }
}

仅此而已。

希望对你有帮助！