无法获取DataGridViewComboBoxCell中最后一个选定的项

Question

我的问题是这样的：我有一个C#应用程序，它有datagridview，它的列中有一些文本框和组合框。所有列都从数据库中获取数据。文本框是只读的。当我要求每行中的值时，我会得到最后一个选定组件的值（即combobox的值，因为文本框是只读的）为null。

例如：

我一排有10个单元格。组合框位于一行中的第7、第8和第9个索引处，其中从0到6的索引为文本框。当我选择其中的3个（按7、8、9的顺序）时，我无法获得9的单元格值。

CCD_ 1是OK的，row.Cells[8].Value正常row.Cells[9].Value是null

当我选择其中的任意两个时，比如说先选择8，然后选择7，我就无法得到7的单元格值。

row.Cells[8].Value正常row.Cells[7].Value是null

当我只选择一个项目，比如9时，我得到的单元格值再次为null。

因此，我得到最后一个选择的DataGridViewComboBoxCell为null。

有人能帮我解决问题吗？谢谢你的帮助。

这是我的代码：

        private void cmbVariable_SelectedIndexChanged(object sender, EventArgs e)
        {
            ComboBox cmb = sender as ComboBox;
            BringQuery(cmb.SelectedItem.ToString());
        }
        private void BringQuery(string option)
        {
            SqlConnection conn = new SqlConnection("Server = 10.2.6.14; Database = TTS; uid = myuser; password = mypassword");
            DataTable dt1 = new DataTable();
            SqlCommand cmd1 = new SqlCommand("select Track_Number, Parking_Area, Mission_Number, Track_Info, Time, Direction, Explanation from Traffic_Run_Table where Op_Type=@myType", conn);
            SqlCommand cmd2 = new SqlCommand("select * from Traffic_Track_Table", conn);
            SqlCommand cmd3 = new SqlCommand("select * from Traffic_Driver order by Id_Number", conn);
            SqlDataAdapter sda1 = new SqlDataAdapter(cmd1);
            cmd1.Parameters.Add(new SqlParameter("myType", option));
            try
            {
                conn.Open();
                sda1.Fill(dt1);
                dataGridView2.AutoGenerateColumns = false;
                foreach (DataGridViewColumn col in dataGridView2.Columns)
                {
                    col.DataPropertyName = col.Name;
                }
                dataGridView2.DataSource = dt1;
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            DataGridViewComboBoxColumn cmbCol1, cmbCol2, cmbCol3;
            SqlDataAdapter sda2 = new SqlDataAdapter(cmd2);
            DataTable dt2 = new DataTable();
            try
            {
                cmbCol1 = new DataGridViewComboBoxColumn();
                cmbCol1.HeaderText = "Track 1";
                cmbCol1.Name = "Track1";
                cmbCol1.DataPropertyName = cmbCol1.Name;
                cmbCol1.ValueType = typeof(int);
                cmbCol1.Width = 50;

                cmbCol2 = new DataGridViewComboBoxColumn();
                cmbCol2.HeaderText = "Track 2";
                cmbCol2.Name = "Track2";
                cmbCol2.DataPropertyName = cmbCol2.Name;
                cmbCol2.ValueType = typeof(int);
                cmbCol2.Width = 50;
                sda2.Fill(dt2);
                dt2.Columns[0].ColumnName = "Track";
                foreach (DataRow dr in dt2.Rows)
                {
                    cmbCol1.Items.Add(Convert.ToInt32(dr["Track"]));
                    cmbCol2.Items.Add(Convert.ToInt32(dr["Track"]));
                }
                dataGridView2.Columns.Add(cmbCol1);
                dataGridView2.Columns.Add(cmbCol2);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            SqlDataAdapter sda3 = new SqlDataAdapter(cmd3);
            DataTable dt3 = new DataTable();
            try
            {
                cmbCol3 = new DataGridViewComboBoxColumn();
                cmbCol3.HeaderText = "Driver";
                cmbCol3.Name = "Driver";
                cmbCol3.DataPropertyName = cmbCol3.Name;
                cmbCol3.ValueType = typeof(string);
                cmbCol3.Width = 260;
                sda3.Fill(dt3);
                dt3.Columns[0].ColumnName = "Id";
                dt3.Columns[1].ColumnName = "Driver";
                dt3.Columns[2].ColumnName = "Mission";
                foreach (DataRow dr in dt3.Rows)
                {
                    cmbCol3.Items.Add(Convert.ToString(dr["Id"]).Trim() + " - " + Convert.ToString(dr["Dirver"]).Trim() + " - " + Convert.ToString(dr["Mission"]).Trim());
                }
                dataGridView2.Columns.Add(cmbCol3);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            conn.Close();
        }
        public string CheckNull(object value, Type objType)
        {
            string retVal = string.Empty;
            if (value == null || value.ToString() == " " || value.ToString() == "")
            {
                if (objType == typeof(int))
                {
                    retVal = "0";
                }
                if (objType == typeof(string))
                {
                    retVal = "-";
                }
            }
            else
            {
                retVal = value.ToString();
            }
            return retVal;
        }
        private void Save_Click(object sender, EventArgs e)
        {
            SqlConnection connForSave = new SqlConnection("Server = 10.2.6.14; Database = TTS; uid = myuser; password = mypassword");
            SqlCommand cmdForSave = new SqlCommand("insert into Traffic_Records values (@type, @trackNumber, @parkingArea, @missionNmb, @trackInfo, @time, @direction, @explanation, @track1, @track2, @driverId, @driverName, @driverMission, @date)", connForSave);
            foreach (DataGridViewRow row in dataGridView2.Rows)
            {
                try
                {
                    dataGridView2[7, row.Index].Selected = false;
                    dataGridView2[8, row.Index].Selected = false;
                    dataGridView2[9, row.Index].Selected = false;
                    connForSave.Open();
                    cmdForSave.Parameters.AddWithValue("type", CheckNull(cmbVairable.SelectedItem.ToString(), typeof(string)));
                    cmdForSave.Parameters.AddWithValue("trackNumber", Convert.ToInt16(CheckNull(row.Cells[0].Value, typeof(int))));
                    cmdForSave.Parameters.AddWithValue("parkingArea", CheckNull(row.Cells[1].Value, typeof(string)));
                    cmdForSave.Parameters.AddWithValue("missionNmb", Convert.ToInt16(CheckNull(row.Cells[2].Value, typeof(int))));
                    cmdForSave.Parameters.AddWithValue("trackInfo", CheckNull(row.Cells[3].Value, typeof(string)));
                    cmdForSave.Parameters.AddWithValue("time", CheckNull(row.Cells[4].Value, typeof(string)));
                    cmdForSave.Parameters.AddWithValue("direction", CheckNull(row.Cells[5].Value, typeof(string)));
                    cmdForSave.Parameters.AddWithValue("explanation", CheckNull(row.Cells[6].Value, typeof(string)));
                    cmdForSave.Parameters.AddWithValue("track1", Convert.ToInt16(CheckNull(row.Cells[7].Value, typeof(int))));
                    cmdForSave.Parameters.AddWithValue("track2", Convert.ToInt16(CheckNull(row.Cells[8].Value, typeof(int))));
                    string[] sArray = null;
                    if (string.Compare(CheckNull(row.Cells[9].Value, typeof(string)), "0") != 0 && string.Compare(CheckNull(row.Cells[9].Value, typeof(string)), "-") != 0)
                    {
                        sArray = row.Cells[9].Value.ToString().Split('-');
                        sArray[0] = sArray[0].Remove(sArray[0].Length - 2, 1);
                        sArray[1] = sArray[1].Remove(0, 1);
                        sArray[1] = sArray[1].Remove(sArray[1].Length - 2, 1);
                        sArray[2] = sArray[2].Remove(0, 1);
                    }
                    else
                    {
                        string temp = "0 - -";
                        sArray = temp.Split(' ');
                    }
                    cmdForSave.Parameters.AddWithValue("driverId", Convert.ToInt16(sArray[0]));
                    cmdForSave.Parameters.AddWithValue("driverName", sArray[1]);
                    cmdForSave.Parameters.AddWithValue("driverMission", sArray[2]);
                    cmdForSave.Parameters.AddWithValue("date", DateTime.Now);
                    cmdForSave.ExecuteNonQuery();
                    cmdForSave.Parameters.Clear();
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message + "n Line Number: " + ex.LineNumber());
                }
                connForSave.Close();
            } 
        }

Answer 1

之所以会发生这种情况，是因为DataGridView不会立即提交用户所做的更改，而是只有在验证了行之后才提交（我认为，这可能是错误的）。所以，在您选择了最后一个值并且没有更改行（所以验证事件没有触发）之后，组合框中的值仍然为null。

要修复此问题，请将CurrentCellDirtyStateChanged（更多信息请点击此处MSDN事件添加到您的网格：

private void GridCurrentCellDirtyStateChanged(object sender, EventArgs e)
{
    dgvAssignedProperties.CommitEdit(DataGridViewDataErrorContexts.Commit);
}

这就是为什么新的价值观被立即投入的原因。