Winform-将方法更改为异步/等待 [英] Winform - changing a method to async/await

问题描述

我有一个winform和六个listbox并排.在每个listbox下都有一个textbox和一个标记为添加"的Button.当您使用EF将某些内容放入textbox并按添加"按钮时，我将更新该listbox的表，然后重新dataBind listbox.这是添加"按钮的事件处理程序之一的示例:

I have a winform with six listbox side-by-side. Under each listbox there is a textbox and a Button labeled "Add." When you put something in the textboxand press the Add button, using EF, I update a table for that listbox and I re-dataBind the listbox. Here's a sample of one of the event handlers for Add button:

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

TypeCategoryAdd功能在下面列出.我想这样做(注意await):

TypeCategoryAdd function is listed below. I want to do this (notice the await):

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

要使TypeCategoryAdd函数在不同的上下文中运行，以便在更新数据库时不会冻结winform UI，我需要做什么?

What do I need to do in order make the TypeCategoryAdd function to run on different context so that the winform UI don't freeze up when DB update is happening?

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;
        }

推荐答案

利用EF 6中的async方法应该做什么:

What you should do it to take advantage of the async methods in EF 6:

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;
        }
    }
}

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