我想验证列表框中输入的项目 [英] I want to validate entered items in a list box

问题描述

我正在从下拉列表中选择一个MC并将其添加到列表框中，我想进行验证，以使您无法重复同一MC.
这是我到目前为止的代码:

I''m selecting an MC from a dropdownlist and adding it into a listbox, I want to validate so that you can''t repeat the same MC.
Here is the code I have so far:

protected void btnAddMC_Click(object sender, EventArgs e)
        {
            if (ddlMCRequired.SelectedIndex == 0)
            {
                System.Windows.Forms.MessageBox.Show("Please select an MC first", "Error!!!", MessageBoxButtons.OK, MessageBoxIcon.Warning);
            }
            else
            {
                lstmc.Items.Add(ddlMCRequired.SelectedItem.ToString());
            }
        }

推荐答案

尝试:

if (!lstmc.Items.Contains(ddlMCRequired.SelectedItem.ToString()))
   {
   ... add your item
   }

[edit]忘记了一个小括号-OriginalGriff [/edit]

[edit]Forgot a close bracket - OriginalGriff[/edit]

这给我一个错误，说最好的重载...具有无效的参数

Its giving me an error saying the best overloaded ... has invalid arguments

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