Question

我在 Windows 窗体类（称为 DataGridView）中有一个 SummaryDataGrid（称为 SummaryForm），我试图通过 ComboBox 下拉选择以编程方式更新（称为 YearComboBox）。 SummaryDataGrid 用户不可编辑，它仅用于以类似电子表格的方式显示信息。我希望能够使用 YearComboBox 让用户选择年份，然后使用 SummaryDataGrid 根据该年份选择更新其值。您可以在下面的链接中看到 SummaryForm 的屏幕截图，其中显示了 2020 年填充的 SummaryDataGrid。

SummaryForm view

YearComboBox 不是数据绑定的，SummaryDataGrid 也不是。为了以编程方式填充 SummaryDataGrid，我通过在 DataGridViewRows 中创建 SummaryForm 然后使用 MainForm 中定义的函数从我的 SQL 数据库中提取数据来填充数据，反过来使用链接到我托管的 SQL Server 的数据集中定义的函数。一些代码示例可以在下面找到。

public partial class SummaryForm : Form
{
    private DataGridViewRow JanuaryRow = new DataGridViewRow();
    private DataGridViewRow FebruaryRow = new DataGridViewRow();
    private DataGridViewRow MarchRow = new DataGridViewRow();
    private DataGridViewRow AprilRow = new DataGridViewRow();
    private DataGridViewRow MayRow = new DataGridViewRow();
    private DataGridViewRow JuneRow = new DataGridViewRow();
    private DataGridViewRow JulyRow = new DataGridViewRow();
    private DataGridViewRow AugustRow = new DataGridViewRow();
    private DataGridViewRow SeptemberRow = new DataGridViewRow();
    private DataGridViewRow OctoberRow = new DataGridViewRow();
    private DataGridViewRow NovemberRow = new DataGridViewRow();
    private DataGridViewRow DecemberRow = new DataGridViewRow();
    private DataGridViewRow TotalRow = new DataGridViewRow();
    private DataGridViewRow AverageRow = new DataGridViewRow();

    private int year = DateTime.Today.Year;
    ...
    // form load event handler
    private void SummaryForm_FormLoad(Object sender, EventArgs e)
    {
        YearComboBox.Text = year.ToString();

        JanuaryRow.CreateCells(SummaryDataGrid);
        FebruaryRow.CreateCells(SummaryDataGrid);
        MarchRow.CreateCells(SummaryDataGrid);
        AprilRow.CreateCells(SummaryDataGrid);
        MayRow.CreateCells(SummaryDataGrid);
        JuneRow.CreateCells(SummaryDataGrid);
        JulyRow.CreateCells(SummaryDataGrid);
        AugustRow.CreateCells(SummaryDataGrid);
        SeptemberRow.CreateCells(SummaryDataGrid);
        OctoberRow.CreateCells(SummaryDataGrid);
        NovemberRow.CreateCells(SummaryDataGrid);
        DecemberRow.CreateCells(SummaryDataGrid);
        TotalRow.CreateCells(SummaryDataGrid);
        AverageRow.CreateCells(SummaryDataGrid);

        // populate january row
        JanuaryRow.Cells[0].Value = "January";
        JanuaryRow.Cells[1].Value = MainFormInstance.BillsOfSaleCountMonth(1, year);
        JanuaryRow.Cells[2].Value = MainFormInstance.BillsOfSaleCashMonth(1, year);
        JanuaryRow.Cells[3].Value = MainFormInstance.BillsOfSaleCreditMonth(1, year);
        JanuaryRow.Cells[4].Value = Convert.ToDecimal(JanuaryRow.Cells[2].Value) + Convert.ToDecimal(JanuaryRow.Cells[3].Value);
        JanuaryRow.Cells[5].Value = MainFormInstance.CashMonth(1, year);
        JanuaryRow.Cells[6].Value = MainFormInstance.CardMonth(1, year);
        JanuaryRow.Cells[7].Value = MainFormInstance.MonthCP(1, year);
        JanuaryRow.Cells[8].Value = MainFormInstance.ExpensesMonthCP(1, year) + MainFormInstance.BillsOfSaleCashMonth(1, year);
        JanuaryRow.Cells[9].Value = Convert.ToDecimal(JanuaryRow.Cells[7].Value) - Convert.ToDecimal(JanuaryRow.Cells[8].Value);
        JanuaryRow.Cells[10].Value = MainFormInstance.MonthCF(1, year);
        JanuaryRow.Cells[11].Value = MainFormInstance.ExpensesMonthCF(1, year);
        JanuaryRow.Cells[12].Value = Convert.ToDecimal(JanuaryRow.Cells[10].Value) - Convert.ToDecimal(JanuaryRow.Cells[11].Value);
        JanuaryRow.Cells[13].Value = MainFormInstance.ExpensesMonthGeneral(1, year);
        JanuaryRow.Cells[14].Value = Convert.ToDecimal(JanuaryRow.Cells[5].Value) + Convert.ToDecimal(JanuaryRow.Cells[6].Value);
        JanuaryRow.Cells[15].Value = Convert.ToDecimal(JanuaryRow.Cells[8].Value) + Convert.ToDecimal(JanuaryRow.Cells[11].Value) + Convert.ToDecimal(JanuaryRow.Cells[13].Value);
        JanuaryRow.Cells[16].Value = Convert.ToDecimal(JanuaryRow.Cells[14].Value) - Convert.ToDecimal(JanuaryRow.Cells[15].Value);
        SummaryDataGrid.Rows.Add(JanuaryRow);
        ...
    }

    // year combo box selection event handler
    private void SummaryForm_YearChanged(Object sender, EventArgs e)
    {
        year = int.Parse(YearComboBox.Text);
        PopulateSummaryDataGrid();
    }

    // populate the summary data grid
    private void PopulateSummaryDataGrid()
    {
        // stubbed
    }

我为 YearComboBox 定义了一个 SelectedValueChanged 事件处理程序，并且最初尝试将每一行的填充移动到与 FormLoad 事件处理程序不同的函数中。这个想法是让 FormLoad 事件处理程序从 SummaryForm 中定义的年份变量更新 YearComboBox 初始 Text 属性，为每一行执行 CreateCells() 调用，然后调用单独的 void 函数来执行填充.但是，在调试时，单独的函数会立即到达尝试编辑单元格的第一个 JanRow 语句，并会说索引为 -1，因此超出范围。我尝试让 SelectedValueChanged 事件触发 FormLoad 事件处理程序，但由于行已被创建和填充，这也不起作用。

所以，我的问题是我怎样才能获得这个下拉选择来更改 FormLoad 事件处理程序中的语句使用的年份（工作正常）并让它用新值重新填充 DataGridView基于更新的年份？

Answer 1

好吧，我似乎在尝试不同的事情时偶然发现了一个解决方案。可能不是最优雅的，但这是我对 PopulateSummaryGrid() 的实现，以防其他人遇到此问题：

// populate the summary data grid
    private void PopulateSummaryDataGrid()
    {
        // update January row
        SummaryDataGrid.Rows[0].Cells[1].Value = MainFormInstance.BillsOfSaleCountMonth(1, year);
        SummaryDataGrid.Rows[0].Cells[2].Value = MainFormInstance.BillsOfSaleCashMonth(1, year);
        SummaryDataGrid.Rows[0].Cells[3].Value = MainFormInstance.BillsOfSaleCreditMonth(1, year);
        SummaryDataGrid.Rows[0].Cells[4].Value = Convert.ToDecimal(SummaryDataGrid.Rows[0].Cells[2].Value) + Convert.ToDecimal(SummaryDataGrid.Rows[0].Cells[3].Value);
        SummaryDataGrid.Rows[0].Cells[5].Value = MainFormInstance.CashMonth(1, year);
        SummaryDataGrid.Rows[0].Cells[6].Value = MainFormInstance.CardMonth(1, year);
        SummaryDataGrid.Rows[0].Cells[7].Value = MainFormInstance.MonthCP(1, year);
        SummaryDataGrid.Rows[0].Cells[8].Value = MainFormInstance.ExpensesMonthCP(1, year) + MainFormInstance.BillsOfSaleCashMonth(1, year);
        SummaryDataGrid.Rows[0].Cells[9].Value = Convert.ToDecimal(SummaryDataGrid.Rows[0].Cells[7].Value) - Convert.ToDecimal(SummaryDataGrid.Rows[0].Cells[8].Value);
        SummaryDataGrid.Rows[0].Cells[10].Value = MainFormInstance.MonthCF(1, year);
        SummaryDataGrid.Rows[0].Cells[11].Value = MainFormInstance.ExpensesMonthCF(1, year);
        SummaryDataGrid.Rows[0].Cells[12].Value = Convert.ToDecimal(SummaryDataGrid.Rows[0].Cells[10].Value) - Convert.ToDecimal(SummaryDataGrid.Rows[0].Cells[11].Value);
        SummaryDataGrid.Rows[0].Cells[13].Value = MainFormInstance.ExpensesMonthGeneral(1, year);
        SummaryDataGrid.Rows[0].Cells[14].Value = Convert.ToDecimal(SummaryDataGrid.Rows[0].Cells[5].Value) + Convert.ToDecimal(SummaryDataGrid.Rows[0].Cells[6].Value);
        SummaryDataGrid.Rows[0].Cells[15].Value = Convert.ToDecimal(SummaryDataGrid.Rows[0].Cells[8].Value) + Convert.ToDecimal(SummaryDataGrid.Rows[0].Cells[11].Value) + Convert.ToDecimal(SummaryDataGrid.Rows[0].Cells[13].Value);
        SummaryDataGrid.Rows[0].Cells[16].Value = Convert.ToDecimal(SummaryDataGrid.Rows[0].Cells[14].Value) - Convert.ToDecimal(SummaryDataGrid.Rows[0].Cells[15].Value);
        ...
        SummaryDataGrid.Refresh();
    }

我还必须删除 FormLoad 事件处理程序的第一条语句，该语句将 YearComboBox 的文本设置为当前年份。这似乎一切正常。

通过组合框选择更新 DataGridView

1 个答案: