假设我有两张桌子：

 work_hours
 work_hours_id | date  | _project_id
     1            1.2.      10
     2            1.2.      11
     3            1.2.      10 

 project
 project_id | project_name
    10           pr1
    11           pr2
    12           pr3

在DataGridView中我想看到这个：

 work_hours_id | date | _person_id | project_name(DataGridViewComboBoxColumn)
     1            1.2.     10            pr1
     2            1.2.     11            pr2
     3            1.2.     10            pr1

我怎么能这样做？
2.如果我使用SqlCommandBuilder将pr1(work_hours_id = 3)更改为pr3(DataGridViewComboBoxColumn),是否可以保存表work_hours中的更改？

 string query = "SELECT work_hours.work_hours_id, work_hours.date FROM work_hours
           LEFT OUTER JOIN project ON work_hours._project_id = project.project_id ORDER BY work_hours.date;
         SELECT * FROM project ORDER BY project_name";

            SqlCommand sqlcmd = new SqlCommand(query, conn);
            da = new SqlDataAdapter(query, connectionString);
            cBuilder = new SqlCommandBuilder(da);
            dt = new DataTable();
            ds = new DataSet();
            da.Fill(dt);
            da.Fill(ds);

            DataGridViewComboBoxColumn columnCb = new DataGridViewComboBoxColumn();
            columnCb.DataPropertyName = "_project_id";

            columnCb.DataSource = ds.Tables[1];
            columnCb.ValueMember = "project_id";
            columnCb.DisplayMember = "project_name";

            bSource = new BindingSource();
            bSource.DataSource = dt;
            dataGridView1.DataSource = bSource;
            dataGridView1.Columns.Add(columnCb);

解决方法:

如果我没有误解你想设置datagridview的组合框列的数据源..你可以这样设置：

/// if you use OfType Method then you will get advantage of to use as normal control
/// means this method will give you advantage of can use all method and properties
/// of the control which you want to implement in DataGridView

/// Controls.OfType method will check all the columns and get an array with 
/// what you give as search criteria..here, the criteria is ComboboxColumn..
/// depends of your need you can give comboboxcell also..

/// Element at method selects the zero based index in array which filtered by criteria
/// if you use only one of the given type then you can use .First() instead of .ElementAt()


yourDataGridViewName.Controls.OfType<DataGridViewComboBoxColumn>()
.ElementAt(indexNoOfTheDGVComboBox).DataSource = YourDataRetrievingMethod; 
//i.e. ds.Tables[indexNoOfTheTable].Columns[IndexOfTheColumn]

/// and you can set DisplayMember and ValueMember as the same way.. 
/// i give combocell and combocolumn together to show the syntax.

yourDataGridViewName.Controls.OfType<DataGridViewComboBoxCell>()
.ElementAt(0).DisplayMember = "YourDisplay";

yourDataGridViewName.Controls.OfType<DataGridViewComboBoxCell>()
.ElementAt(0).ValueMember = "YourValue"; 

关于第二个问题..如果你问我,那么我更喜欢：要控制“意外节省”,在行的末尾放置一个buttonCell ..当用户更改某些行时,应单击保存按钮.然后在按钮单击方法可以保存更改为正常的插入或更新方法..

只有2个差异..

1-)你需要使用Cell_Click事件并确保使用OfType()方法而不是普通的Button _Click事件进行按钮检查

2-)取决于项目需求,您需要获取DataGridView的RowIndex和/或Cell Address()才能获取并将值传递给SQLQuery