当另一个组合框更改选定值时设置组合框选定项c#

Question

class ComboBoxCompany
{
    public string Code;
    public string Name;
    public string Database;

    public ComboBoxCompany(string code, string name, string database)
    {
        Code = code;  Name = name; Database = database;
    }

    public override string ToString()
    {
        // Generates the text shown in the combo box
        return Name;
    }
}

class ComboBoxDatabase
{
    public string cmpName;
    public string dbName;

    public ComboBoxDatabase(string cmpname, string dbname)
    {
        cmpName = cmpname; dbName = dbname;
    }

    public override string ToString()
    {
        // Generates the text shown in the combo box
        return cmpName + " - " + dbName;
    }
}

这些是 2 个组合框的类，所以当我选择第一个组合框（ComboBoxCompany）的值时，我希望第二个组合框（ComboBoxDatabase）从第一个组合框“数据库”中选择“dbName”-值-价值

我试过了，还是不行

    private void cbxBranch_SelectedIndexChanged(object sender, EventArgs e)
    {
        cbxDatabase.SelectedItem = (cbxCompany.SelectedItem as ComboBoxCompany).Database;
    }

Answer 1

通过设置 (cbxCompany.SelectedItem as ComboBoxCompany).Database 您尝试将所选项目设置为不“存在”的数据库字符串，因为您似乎添加了一个类作为组合框项。

您需要将 SelectedItem 设置为真实对象。您可以使用 linq（示例代码）搜索此内容：

var company = cbxCompany.SelectedItem as ComboBoxCompany;
if(company == null)
   return;
var dbItem = _databaseComboBoxItems.FirstOrDefault(x=>x.CompanyName = company.CompanyName && x.Database == company.DatabaseName);
if(dbItem == null)
  return;
 cbxDatabase.SelectedItem = dbItem;