Question

我有一个winform并列有六个listbox。每个listbox下都有textbox和Button标记为＆＃34;添加。＆＃34;当您在textbox中添加内容并按下添加按钮后，使用EF，我会更新listbox的表格，然后重新dataBind listbox。这是“添加”按钮的一个事件处理程序的示例：

private void btnOfferType_Click(object sender, EventArgs e)
{
    TypeCategoryAdd("OfferType", tbOfferType.Text.Trim());
}

TypeCategoryAdd功能如下所示。我想这样做（注意await）：

private async void btnOfferType_Click(object sender, EventArgs e)
{
    await TypeCategoryAdd("OfferType", tbOfferType.Text.Trim());
}

我需要做些什么才能让TypeCategoryAdd函数在不同的上下文中运行，以便在发生数据库更新时winform用户界面不会冻结？

private void TypeCategoryAdd (string table, string item)
{
    if (string.IsNullOrEmpty(item)) return;

    using (MenuGenerator.NewArchMenuGeneratorEntities con = new NewArchMenuGeneratorEntities())
    {
        switch (table)
        {
            case "OfferType":
                if (con.OfferTypes.Any(x=>x.Name == item))
                {
                    MessageBox.Show("There is already a " + item + " on the list!");
                    tbOfferType.Text = "";
                    return;
                }
                OfferType ot = new OfferType();
                ot.Name = item;
                con.OfferTypes.Add(ot);
                try
                {
                    con.SaveChanges();
                    tbOfferType.Text = "";
                    lstOfferType.DataSource = con.OfferTypes.OrderBy(x=>x.Id).ToList();                    
                }
                catch (Exception ex)
                {
                    MessageBox.Show("Error " + ex.ToString());
                }
                break;                

            }
            return;
        }

Answer 1

您应该如何利用EF 6中的async方法：

private async Task TypeCategoryAdd (string table, string item)
{
    if (string.IsNullOrEmpty(item)) return;

    using (MenuGenerator.NewArchMenuGeneratorEntities con = new NewArchMenuGeneratorEntities())
    {
        switch (table)
        {
            case "OfferType":
                if (await con.OfferTypes.AnyAsync(x=>x.Name == item))
                {
                    MessageBox.Show("There is already a " + item + " on the list!");
                    tbOfferType.Text = "";
                    return;
                }
                OfferType ot = new OfferType();
                ot.Name = item;
                con.OfferTypes.Add(ot);
                try
                {
                    await con.SaveChangesAsync();
                    tbOfferType.Text = "";
                    lstOfferType.DataSource = await con.OfferTypes.OrderBy(x=>x.Id).ToListAsync();
                }
                catch (Exception ex)
                {
                    MessageBox.Show("Error " + ex.ToString());
                }
                break;                

            }
            return;
        }
    }
}

Answer 2

您可以将数据库访问权限包含在Task和await上。

private async void btnOfferType_Click(object sender, EventArgs e)
{
    await Task.Run(()=>TypeCategoryAdd("OfferType", tbOfferType.Text.Trim()));
}

Winform - 将方法更改为异步/等待

2 个答案: