如果重复选择，则下拉列表选定索引设置为 0

本文关键字：索引 设置 下拉列表 选择 如果 | 更新日期: 2023-09-27 18:36:35

我有一个 linq 查询，它检查所有 6 个下拉列表是否有任何重复。

为此，目前我为所有下拉列表设置 SelectedIndex 为 0。取而代之的是，我想要这两个下拉菜单。SelectedIndex=0 具有相同的 SelectedValue。

        var allIndexes = new List<int>
        {
                drpdwnlst_Seq1.SelectedIndex,
                drpdwnlst_Seq2.SelectedIndex,
                drpdwnlst_Seq3.SelectedIndex,
                drpdwnlst_Seq4.SelectedIndex,
                drpdwnlst_Seq5.SelectedIndex,
                drpdwnlst_Seq6.SelectedIndex
        };
        var noSelectedIndexIsTheSame = allIndexes.Where(x => x != 0)
                                     .GroupBy(x => x)
                                     .All(x => x.Count() == 1);
        if (!noSelectedIndexIsTheSame)
        {
            ScriptManager.RegisterStartupScript(Page, Page.GetType(), "AdminUserError", "alert('Selection Rrepeated.'); ", true);
            drpdwnlst_Seq1.SelectedIndex = 0;
            drpdwnlst_Seq2.SelectedIndex = 0;
            drpdwnlst_Seq3.SelectedIndex = 0;
            drpdwnlst_Seq4.SelectedIndex = 0;
            drpdwnlst_Seq5.SelectedIndex = 0;
            drpdwnlst_Seq6.SelectedIndex = 0;
        }

如果重复选择，则下拉列表选定索引设置为 0

您可以将列表更改为以下定义，（以便您可以保留大部分逻辑）

List<KeyValuePair<DropDownList, int>> allIndexes = new List<KeyValuePair<DropDownList, int>>
{
    new KeyValuePair<DropDownList, int>(drpdwnlst_Seq1, drpdwnlst_Seq1.SelectedIndex),
    new KeyValuePair<DropDownList, int>(drpdwnlst_Seq2, drpdwnlst_Seq2.SelectedIndex),
    new KeyValuePair<DropDownList, int>(drpdwnlst_Seq3, drpdwnlst_Seq3.SelectedIndex),
    new KeyValuePair<DropDownList, int>(drpdwnlst_Seq4, drpdwnlst_Seq4.SelectedIndex),
    new KeyValuePair<DropDownList, int>(drpdwnlst_Seq5, drpdwnlst_Seq5.SelectedIndex),
    new KeyValuePair<DropDownList, int>(drpdwnlst_Seq6, drpdwnlst_Seq6.SelectedIndex)
};
var groups = allIndexes.Where(x => x.Value != 0).GroupBy(x => x.Value);
boolean noSelectedIndexIsTheSame = groups.All(g => g.Count() == 1);
if (!noSelectedIndexIsTheSame)
{
    ScriptManager.RegisterStartupScript(Page, Page.GetType(), "AdminUserError", "alert('Selection Rrepeated.'); ", true);
    foreach (var g in groups) 
    {
        if (g.Count() == 1) 
        {
            continue;
        }
        foreach (var kvp in g)
        {
            kvp.Key.SelectedIndex = 0;
        }
    }
}

这样，您就有了组合框的引用 + 当前选定的索引，按 KeyValuePair.Value 分组，并且您有一个单独的布尔值检查是否没有相同的索引。如果是，它将循环组，如果每个组找到超过 1 个，请重置这些组

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