请试试这个方法，它对我很有效:

Combobox1.items[Combobox1.selectedIndex] = "replaced text";

我已经创建了一个函数，它将返回值的索引

        public static int SelectByValue(ComboBox comboBox, string value)
        {
            int i = 0;
            for (i = 0; i <= comboBox.Items.Count - 1; i++)
            {
                DataRowView cb;
                cb = (DataRowView)comboBox.Items[i];
                if (cb.Row.ItemArray[0].ToString() == value)// Change the 0 index if your want to Select by Text as 1 Index
                {
                    return i;
                }
            }
            return -1;
        }

comboBox1.SelectedItem.Text = "test1";

_cmbTemplates.SelectedText = "test1"

或者

_cmbTemplates.SelectedItem= _cmbTemplates.Items.Equals("test1");

如果组合框中的项目是字符串，您可以尝试:

comboBox1.SelectedItem = "test1";

这对我有用.....

comboBox.DataSource.To<DataTable>().Select(" valueMember = '" + valueToBeSelected + "'")[0]["DislplayMember"];