DataGridViewComboBoxCell valueValue与绑定的DataGridViewComboBoxCell无效

Question

我有一个带有两个DatagridView的DataGridViewComboBoxCell：

1. 管理
2. 雇员。

我想做的是，当我从第一届

DataGridViewComboBoxCell，我会得到所选员工的名单

第二DataGridViewComboBoxCell的管理。我绑定了第一个

DataGridViewComboBoxCell手动到administrationBindingSource，我尝试了

this answer code，这是我使用的代码：

dataGridView1.CellValueChanged += new DataGridViewCellEventHandler(dataGridView1_CellValueChanged);
dataGridView1.CurrentCellDirtyStateChanged += new EventHandler(dataGridView1_CurrentCellDirtyStateChanged);

void dataGridView1_CurrentCellDirtyStateChanged(object sender, EventArgs e)
    {
        if (dataGridView1.IsCurrentCellDirty)
        {
            // This fires the cell value changed handler below
            dataGridView1.CommitEdit(DataGridViewDataErrorContexts.Commit);
        }
    }

private void dataGridView1_CellValueChanged(object sender, DataGridViewCellEventArgs e)
{
    if (e.RowIndex == -1)
    {
        return;
    }

    DataGridViewComboBoxCell cb = (DataGridViewComboBoxCell)dataGridView1.CurrentRow.Cells["administrationColumn"];
    int item = 0;
    if (cb.Value != null)
    {
        item = (Int32)cb.Value;
        selectEmployee(item);
        dataGridView1.Invalidate();
    }

}
private void selectEmployee(int idAdministration)
{
    if (con.State != ConnectionState.Open)
    {
        con.Open();
    }
    SqlCommand Cmd = new SqlCommand("SELECT * FROM Employee WHERE IdAdministration = @idAdministration", con);
    Cmd.Parameters.AddWithValue("@idAdministration", idAdministration);
    DataTable Dt = new DataTable();
    Dt.Load(Cmd.ExecuteReader());
    DataGridViewComboBoxCell cb = (DataGridViewComboBoxCell)dataGridView1.CurrentRow.Cells["Employee"];
    cb.DataSource = Dt;
    cb.DisplayMember = "Name";
    cb.ValueMember = "CodeEmployee";
    con.Close();
}

这段代码在第一次运行良好，但是当我试图更新admininstration值时，我得到了以下错误消息：

DataGridViewComboBoxCell值无效

怎么修呢？

Answer 1

在空中重新绑定员工单元之前，尝试清除它的值。

"selectEmployee"，类似于：

private void selectEmployee(int idAdministration)
{
    if (con.State != ConnectionState.Open)
    {
        con.Open();
    }
    SqlCommand Cmd = new SqlCommand("SELECT * FROM Employee WHERE IdAdministration = @idAdministration", con);
    Cmd.Parameters.AddWithValue("@idAdministration", idAdministration);
    DataTable Dt = new DataTable();
    Dt.Load(Cmd.ExecuteReader());
    DataGridViewComboBoxCell cb = (DataGridViewComboBoxCell)dataGridView1.CurrentRow.Cells["Employee"];
    cb.Value = null; //add this
    cb.DataSource = Dt;
    cb.DisplayMember = "Name";
    cb.ValueMember = "CodeEmployee";
    con.Close();
}