如何从 ComboBox C# Winforms 中获取 ValueMember 值？答案

【问题标题】：How to get ValueMember value from ComboBox C# Winforms?如何从 ComboBox C# Winforms 中获取 ValueMember 值？
【发布时间】：2021-08-07 19:55:39
【问题描述】：

我在尝试获取我设置的 ValueMember 值时遇到了一些问题。我正在尝试使用组合框来选择 Windows 窗体报告。我可以得到名称，但不能得到 RptValue。这是我的代码：

        private class Data
    {
        public string Name { get; set; }
        public string RptValue { get; set; }
    }

    private void BaseForm_Load(object sender, EventArgs e)
    {
        this.rvDoctorReportViewer.RefreshReport();
        comboBox1.Items.Add(new Data { Name="Select", RptValue="Select"});
        comboBox1.Items.Add(new Data { Name = "All Food Values", RptValue = "AllFoodValues.rdlc" });
        comboBox1.Items.Add(new Data { Name = "All Readings", RptValue = "AllReadings.rdlc" });
        comboBox1.Items.Add(new Data { Name = "Avg Food Values by Date", RptValue = "AvgFoodValuesByDate.rdlc" });
        comboBox1.Items.Add(new Data { Name = "Avg Food Values by Meal", RptValue = "AvgFoodValuesByMeal.rdlc" });
        comboBox1.Items.Add(new Data { Name = "Avg Readings by Date", RptValue = "AvgReadingsByDate.rdlc" });
        comboBox1.Items.Add(new Data { Name = "Avg Readings by Time", RptValue = "AvgReadingsByTime.rdlc" });
        comboBox1.Items.Add(new Data { Name = "Avg Readings by Event", RptValue = "AvgReadingsByEvent.rdlc" });
        comboBox1.Items.Add(new Data { Name = "Blood Pressure Chart", RptValue = "BPChart.rdlc" });
        comboBox1.Items.Add(new Data { Name = "Blood Pressure Report", RptValue = "BPReport.rdlc" });
        comboBox1.Items.Add(new Data { Name = "Detail Food Values by Meal", RptValue = "DetailFoodValuesByMeal.rdlc" });
        comboBox1.Items.Add(new Data { Name = "Doctor Detail Report", RptValue = "DoctorDetailReport.rdlc" });
        comboBox1.Items.Add(new Data { Name = "Food Chart", RptValue = "FoodChart.rdlc" });
        comboBox1.Items.Add(new Data { Name = "Pumper Detail Report", RptValue = "PumperDetailReport.rdlc" });
        comboBox1.Items.Add(new Data { Name = "Reading Charts", RptValue = "ReadingCharts.rdlc" });
        comboBox1.Items.Add(new Data { Name = "Total Daily Food Intake", RptValue = "TotalIntakeDailyFood.rdlc" });
        comboBox1.DisplayMember = "Name"; // This works fine
        comboBox1.ValueMember = "RptValue"; // This is the problem. It renders as RptValue instead of the value
        comboBox1.SelectedIndex = 0;
    }

    private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (comboBox1.SelectedIndex > 0)
        {
            string strReport;
            strReport = "ReportViewer." + comboBox1.ValueMember.ToString();
            rvDoctorReportViewer.Reset();
            rvDoctorReportViewer.LocalReport.ReportEmbeddedResource = strReport;
            this.rvDoctorReportViewer.RefreshReport();
        }
    }

【问题讨论】：

标签： c# winforms report

【解决方案1】：

您应该使用DataSource 属性。试试这个：

BindingList<Data> _comboItems = new BindingList<Data>(); 
_comboItems.Add(new Data { Name = "Select", RptValue = "Select" });
_comboItems.Add(new Data { Name = "All Food Values", RptValue = "AllFoodValues.rdlc" });
...
comboBox1.DataSource = _comboItems;
comboBox1.DisplayMember = "Name";
comboBox1.ValueMember = "RptValue";

然后访问选中的值：

strReport = "ReportViewer." + comboBox1.SelectedValue;

【讨论】：

好的，现在我在报告本身上遇到了另一个错误。它说“本地报告处理期间发生错误。尚未指定“报告名称”的报告定义。对象引用未设置为对象的实例。”有什么想法吗？
@bbcompent1 没有看到一些代码就不能肯定地说什么。 :) 我猜它与ReportPath 有关（但我不确定）。我会建议发布一个关于这个特定问题的新问题。
好的，这是该问题的链接：stackoverflow.com/questions/16024549/…

【解决方案2】：

  String s;
  s=comboBox1.SelectedValue.toString()

【讨论】：

【解决方案3】：

这对我有用：

    combobox.valuemember="id"
    combobox.displaymember="name"
    combobox.datasource=dt

【讨论】：