如果用户开始输入组合框集合中包含的字符，如何让组合框显示文本？ C＃ [英] How do I get combobox to display the text if the user starts typing characters contained on the combobox collection? C#
问题描述
例如
该集合有一个项目学生
如果用户开始输入S，组合框文本应查找该字符并开始显示/提出学生文本。如果字符不匹配则保持空白
我尝试过：
private void cmbType_TextChanged（object sender，EventArgs e）
{
if（cmbType.Text.Contains（cmbType.Text.ToUpper（）））
{
var items = this.cmbType.GetItemText（this.cmbType.SelectedItem）;
// var type = cmbType.Items.ToString（）。Where （c =>
cmbType.Text.ToUpper（）。包含（cmbType.Text.ToUpper（）））;
cmbType.Text = items;
}
}
for example
the collection has an item "Student"
if the user start typing "S", the combobox text should look for that character and start displaying/ suggesting the "Student" text. if character dont match it stays blank
What I have tried:
private void cmbType_TextChanged(object sender, EventArgs e)
{
if (cmbType.Text.Contains(cmbType.Text.ToUpper()))
{
var items = this.cmbType.GetItemText(this.cmbType.SelectedItem);
//var type = cmbType.Items.ToString().Where(c =>
cmbType.Text.ToUpper().Contains(cmbType.Text.ToUpper()));
cmbType.Text = items;
}
}
推荐答案
试试这个：
class DummyComboBoxItem
{
公共字符串显示名称
{
get
{
返回做出选择......;
}
}
}
公共部分类mainForm：表格
{
私人DummyComboBoxItem placeholde r = new DummyComboBoxItem（）;
public mainForm（）
{
InitializeComponent（）;
myComboBox.DisplayMember =DisplayName;
myComboBox.Items.Add（占位符）;
foreach（对象中的对象o）
{
myComboBox .Items.Add（o）;
}
myComboBox.SelectedItem =占位符;
}
private void myComboBox_SelectedIndexChanged（object sender，EventArgs e）
{
if（myComboBox.SelectedItem == null）return;
if（myComboBox.SelectedItem == placeholder）返回;
/ *
做你的东西
* /
myComboBox.Items.Add（占位符）;
myComboBox.SelectedItem =占位符;
}
private void myComboBox_DropDown（object sender，EventArgs e）
{
myComboBox.Items.Remove（占位符）;
}
private void myComboBox_Leave（object sender，EventArgs e）
{
//这包括用户中止选择（通过点击或选择系统空下拉选项）
//控件可能无法立即更改，但如果用户点击其他任何地方则会重置
if（myComboBox.SelectedItem！= placeholder）
{
if（！myComboBox.Items.Contains（占位符））myComboBox.Items.Add（占位符）;
myComboBox.SelectedItem =占位符;
}
}
}
try this:
class DummyComboBoxItem
{
public string DisplayName
{
get
{
return "Make a selection ...";
}
}
}
public partial class mainForm : Form
{
private DummyComboBoxItem placeholder = new DummyComboBoxItem();
public mainForm()
{
InitializeComponent();
myComboBox.DisplayMember = "DisplayName";
myComboBox.Items.Add(placeholder);
foreach(object o in Objects)
{
myComboBox.Items.Add(o);
}
myComboBox.SelectedItem = placeholder;
}
private void myComboBox_SelectedIndexChanged(object sender, EventArgs e)
{
if (myComboBox.SelectedItem == null) return;
if (myComboBox.SelectedItem == placeholder) return;
/*
do your stuff
*/
myComboBox.Items.Add(placeholder);
myComboBox.SelectedItem = placeholder;
}
private void myComboBox_DropDown(object sender, EventArgs e)
{
myComboBox.Items.Remove(placeholder);
}
private void myComboBox_Leave(object sender, EventArgs e)
{
//this covers user aborting the selection (by clicking away or choosing the system null drop down option)
//The control may not immedietly change, but if the user clicks anywhere else it will reset
if(myComboBox.SelectedItem != placeholder)
{
if(!myComboBox.Items.Contains(placeholder)) myComboBox.Items.Add(placeholder);
myComboBox.SelectedItem = placeholder;
}
}
}
表格加载期间......
During form load...
// set up source for combo items
string[] items = { "item1", "Student", "Teacher", "Professor", "Teaching Assistent" };
// configure autocompletion for the combobox
AutoCompleteStringCollection allowedTypes = new AutoCompleteStringCollection();
allowedTypes.AddRange(items);
comboBox1.AutoCompleteCustomSource = allowedTypes;
comboBox1.AutoCompleteMode = AutoCompleteMode.SuggestAppend;
comboBox1.AutoCompleteSource = AutoCompleteSource.CustomSource;
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