将图像和字符串添加到组合框
Add an Image and String to a Combobox
查看所有相关主题后，仍然找不到 suitable 答案来全面说明我们如何完成此任务。 （此处使用 Winforms，而非 WPF）
我从两个不同的数据 table 列填充一个组合框，引用用户列表和用户组列表。打开组合框时，两列都变成一个列表。我想要有两个图像（或图标），一个代表用户的项目，另一个代表用户组的图像。想要在文本之前显示图像（文本是从数据中提取的名称table）
我意识到我不能在没有更多代码的情况下简单地混合和匹配两种不同的对象类型，即字符串和图像，但下面的示例，通俗地说就是我想要实现的目标。请有人指教
private void AddUsersGroupsComboboxPopulate()
{
// Clear the comobox before re-populating.
AddUserGroupCombobox.Items.Clear();
// Fill the combobox with a list of the User Groups names.
for (int i = 0; i < DB_UserGroups.userGroupsDataTable.Rows.Count; i++)
{
AddUserGroupCombobox.Items.Add(Image1 + DB_UserGroups.userGroupsDataTable.Rows[i]["UserGroup"]);
}
// Fill the combobox with a list of the User Account names.
for (int i = 0; i < DB_Users.userAccountsDataTable.Rows.Count; i++)
{
AddUserGroupCombobox.Items.Add(Image2 + DB_Users.userAccountsDataTable.Rows[i]["Username"]);
}
}
好的，经过 16 个小时的摸索，我终于成功了！
解决方案概述：
我的 APP 包含一个 Windows 表单（不是 WPF），用于创建电子邮件用户和群组，以便在软件中通知事件。我创建了一个组合框，它从两个不同的数据 table 来源（一个来源的用户组和另一个来源的用户帐户）中提取项目，目的是管理员可以创建电子邮件收件人用户和组。
我真正纠结的部分是配置组合框以允许使用图标（导入的图像）和文本显示在组合框列表中。部分挑战是让我的头脑围绕所有者绘制 属性 并完全通过代码将布局创建为自定义实体。我在网上找不到任何完整的示例，所以不得不四处冲浪，经过大量的反复试验，我最终找到了那里。
我在下面的代码中添加了大量注释，希望其他人能从我今天经历的痛苦中受益！。我的环境可能有点定制化，但花点时间检查代码，您很快就会明白我放在一起的想法。希望这有帮助:)
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
private void NotificationsForm_Load(object sender, EventArgs e)
{
PopulateUsersGroupsList(); // Used to create the list of User Groups & User Accounts when the form opens.
log.Info("NotificationsForm Opened");
}
// Create an image list that will be used for the combobox icons
readonly static ImageList imageListEmailRecipients = new ImageList();
// Create an List that will be used to store the user account and user group names from the two different data tables.
public static readonly List<KeyValuePair<string, string>> emailRecipientsUserList = new List<KeyValuePair<string, string>>();
/// <summary>
/// This method is used to create a list to hold the values pulled from two different data tables.
/// The information pulled provides the list with the names of the User Groups & User Accounts.
/// Note: When the Windows Form closes, the closing method runs the command 'emailRecipientsUserList.Clear()'
/// in order to ensure that the list is cleared and does not continue to build up with dulicate entries each
/// time the form is opened.
/// </summary>
private void PopulateUsersGroupsList()
{
// Add the two images to the image list, images are loaded from the properties resources folder.
// These images will be used as icons to display in the combobox.
imageListEmailRecipients.Images.Add((Image)(new Bitmap(Properties.Resources.UserGroup2)));
imageListEmailRecipients.Images.Add((Image)(new Bitmap(Properties.Resources.UserAccount)));
// Add a default string to the list for the combobox default value, prompting the user to make their selection
// before the open up the dropdown combobox.
emailRecipientsUserList.Add(new KeyValuePair<string, string>("", "--Select--"));
// Add each User Group from the data table to the list. KeyValuePairs are used so we can differentiate
// between the User Groups list and User Accounts list.
for (int i = 0; i < DB_UserGroups.userGroupsDataTable.Rows.Count; i++)
{
emailRecipientsUserList.Add(new KeyValuePair<string, string>("UserGroup", DB_UserGroups.userGroupsDataTable.Rows[i]["UserGroup"].ToString()));
}
// Add each User Account from the data table to the list. KeyValuePairs are used so we can differentiate
// between the User Groups list and User Accounts list.
for (int i = 0; i < DB_Users.userAccountsDataTable.Rows.Count; i++)
{
//emailRecipientsUserList.Add(DB_Users.userAccountsDataTable.Rows[i]["Username"].ToString());
emailRecipientsUserList.Add(new KeyValuePair<string, string>("Username", DB_Users.userAccountsDataTable.Rows[i]["Username"].ToString()));
}
// Run the method below that will populate the combobox with the User Groups & User Accounts from the list.
AddUsersGroupsComboboxPopulate();
}
/// <summary>
/// Method used to populate the combobox using the 'emailRecipientsUserList' created from the method above.
/// </summary>
private void AddUsersGroupsComboboxPopulate()
{
// Clear the comobox before re-populating.
AddUserGroupCombobox.Items.Clear();
// Map the combobox's data source to the 'emailRecipientsUserList' source.
this.AddUserGroupCombobox.DataSource = emailRecipientsUserList;
// Confirure the combobox to the show the 'Value' portion ONLY from the KeyValuePair
// value set found in the 'emailRecipientsUserList'.
this.AddUserGroupCombobox.DisplayMember = "Value";
// Configure the combobox to utilise the Key from the 'emailRecipientsUserList' as its member value.
this.AddUserGroupCombobox.ValueMember = "Key";
// Set the combobox to owner draw mode - otherwise you cannot change the output style to your own format.
AddUserGroupCombobox.DrawMode = DrawMode.OwnerDrawFixed;
// Instruct the combobox to draw itself using the 'AddUserGroupCombobox_DrawItem' method below.
AddUserGroupCombobox.DrawItem += AddUserGroupCombobox_DrawItem;
// Set the default height for each of the items displayed in the combobox.
AddUserGroupCombobox.ItemHeight = 20;
}
// Mouse index used to reference the position of the cursor when navigating up and down the combobox list.
private readonly int _MouseIndex = -1;
/// <summary>
/// This method is used to draw the items from the 'emailRecipientsUserList' into the combobox,
/// using an owner draw custom format so we can show the the User Group & User
/// Account icons adjacent their relevant names in the combobox list.
///
/// In the method above, we created the 'emailRecipientsUserList' that contains data columns
/// from two different data tables, the first datatable holds the names of the User Groups and the second
/// holds the User Accounts. We're utilizing the KeyValuePair in order to provide a
/// means of applying some logic to the population of our combobox in order to differentiate
/// between a User Group and a User Account. This allows us to dynamically
/// assign the relevant icon display, adjacent each of the items in the combobox list.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void AddUserGroupCombobox_DrawItem(object sender, DrawItemEventArgs e)
{
// Set the textBrush color to Windows Text.
Brush textBrush = SystemBrushes.WindowText;
if (e.Index > -1)
{
// Highlight the combobox item when the mouse cursor hovers over the item in the dropdown list.
if (e.Index == _MouseIndex)
{
e.Graphics.FillRectangle(SystemBrushes.HotTrack, e.Bounds);
textBrush = SystemBrushes.HighlightText;
}
else
{
// Highlight the combobox item when slected in the dropdown list.
if ((e.State & DrawItemState.Selected) == DrawItemState.Selected)
{
e.Graphics.FillRectangle(SystemBrushes.Highlight, e.Bounds);
textBrush = SystemBrushes.HighlightText;
}
else
{
// Restore background colour to deafult when the mouse leaves the item.
e.Graphics.FillRectangle(SystemBrushes.Window, e.Bounds);
}
}
// Draw the string i.e populate the combobox with the list of the text names
// for the User groups & User Accounts
e.Graphics.DrawString(emailRecipientsUserList[e.Index].Value.ToString(), e.Font, textBrush, e.Bounds.Left + 20, e.Bounds.Top);
// IF Statements below are used to determine which icon to display in the drop down list, depending on
// whether the comboxo item is a User Group or User Account name.
if (emailRecipientsUserList[e.Index].Key == "UserGroup")
{
// Image list index '0' represents the icon image for the User Group.
e.Graphics.DrawImage(imageListEmailRecipients.Images[0], e.Bounds.Left, e.Bounds.Top);
}
if (emailRecipientsUserList[e.Index].Key == "Username")
{
// Image list index '0' represents the icon image for the User Account.
e.Graphics.DrawImage(imageListEmailRecipients.Images[1], e.Bounds.Left, e.Bounds.Top);
}
}
}
在您的图像中，它在选择框中显示了图像和文本，当我完成此操作后，我得到了图像和文本列表，但是一旦选择，只有文本显示在框中，我是不是错过了什么。
我已经解决了更改ComboBox.DropDownStyle = ComboBoxStyle.DropDownList
这解决了问题。
查看所有相关主题后，仍然找不到 suitable 答案来全面说明我们如何完成此任务。 （此处使用 Winforms，而非 WPF）
我从两个不同的数据 table 列填充一个组合框，引用用户列表和用户组列表。打开组合框时，两列都变成一个列表。我想要有两个图像（或图标），一个代表用户的项目，另一个代表用户组的图像。想要在文本之前显示图像（文本是从数据中提取的名称table）
我意识到我不能在没有更多代码的情况下简单地混合和匹配两种不同的对象类型，即字符串和图像，但下面的示例，通俗地说就是我想要实现的目标。请有人指教
private void AddUsersGroupsComboboxPopulate()
{
// Clear the comobox before re-populating.
AddUserGroupCombobox.Items.Clear();
// Fill the combobox with a list of the User Groups names.
for (int i = 0; i < DB_UserGroups.userGroupsDataTable.Rows.Count; i++)
{
AddUserGroupCombobox.Items.Add(Image1 + DB_UserGroups.userGroupsDataTable.Rows[i]["UserGroup"]);
}
// Fill the combobox with a list of the User Account names.
for (int i = 0; i < DB_Users.userAccountsDataTable.Rows.Count; i++)
{
AddUserGroupCombobox.Items.Add(Image2 + DB_Users.userAccountsDataTable.Rows[i]["Username"]);
}
}
好的，经过 16 个小时的摸索，我终于成功了！
解决方案概述：
我的 APP 包含一个 Windows 表单（不是 WPF），用于创建电子邮件用户和群组，以便在软件中通知事件。我创建了一个组合框，它从两个不同的数据 table 来源（一个来源的用户组和另一个来源的用户帐户）中提取项目，目的是管理员可以创建电子邮件收件人用户和组。
我真正纠结的部分是配置组合框以允许使用图标（导入的图像）和文本显示在组合框列表中。部分挑战是让我的头脑围绕所有者绘制 属性 并完全通过代码将布局创建为自定义实体。我在网上找不到任何完整的示例，所以不得不四处冲浪，经过大量的反复试验，我最终找到了那里。
我在下面的代码中添加了大量注释，希望其他人能从我今天经历的痛苦中受益！。我的环境可能有点定制化，但花点时间检查代码，您很快就会明白我放在一起的想法。希望这有帮助:)
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
private void NotificationsForm_Load(object sender, EventArgs e)
{
PopulateUsersGroupsList(); // Used to create the list of User Groups & User Accounts when the form opens.
log.Info("NotificationsForm Opened");
}
// Create an image list that will be used for the combobox icons
readonly static ImageList imageListEmailRecipients = new ImageList();
// Create an List that will be used to store the user account and user group names from the two different data tables.
public static readonly List<KeyValuePair<string, string>> emailRecipientsUserList = new List<KeyValuePair<string, string>>();
/// <summary>
/// This method is used to create a list to hold the values pulled from two different data tables.
/// The information pulled provides the list with the names of the User Groups & User Accounts.
/// Note: When the Windows Form closes, the closing method runs the command 'emailRecipientsUserList.Clear()'
/// in order to ensure that the list is cleared and does not continue to build up with dulicate entries each
/// time the form is opened.
/// </summary>
private void PopulateUsersGroupsList()
{
// Add the two images to the image list, images are loaded from the properties resources folder.
// These images will be used as icons to display in the combobox.
imageListEmailRecipients.Images.Add((Image)(new Bitmap(Properties.Resources.UserGroup2)));
imageListEmailRecipients.Images.Add((Image)(new Bitmap(Properties.Resources.UserAccount)));
// Add a default string to the list for the combobox default value, prompting the user to make their selection
// before the open up the dropdown combobox.
emailRecipientsUserList.Add(new KeyValuePair<string, string>("", "--Select--"));
// Add each User Group from the data table to the list. KeyValuePairs are used so we can differentiate
// between the User Groups list and User Accounts list.
for (int i = 0; i < DB_UserGroups.userGroupsDataTable.Rows.Count; i++)
{
emailRecipientsUserList.Add(new KeyValuePair<string, string>("UserGroup", DB_UserGroups.userGroupsDataTable.Rows[i]["UserGroup"].ToString()));
}
// Add each User Account from the data table to the list. KeyValuePairs are used so we can differentiate
// between the User Groups list and User Accounts list.
for (int i = 0; i < DB_Users.userAccountsDataTable.Rows.Count; i++)
{
//emailRecipientsUserList.Add(DB_Users.userAccountsDataTable.Rows[i]["Username"].ToString());
emailRecipientsUserList.Add(new KeyValuePair<string, string>("Username", DB_Users.userAccountsDataTable.Rows[i]["Username"].ToString()));
}
// Run the method below that will populate the combobox with the User Groups & User Accounts from the list.
AddUsersGroupsComboboxPopulate();
}
/// <summary>
/// Method used to populate the combobox using the 'emailRecipientsUserList' created from the method above.
/// </summary>
private void AddUsersGroupsComboboxPopulate()
{
// Clear the comobox before re-populating.
AddUserGroupCombobox.Items.Clear();
// Map the combobox's data source to the 'emailRecipientsUserList' source.
this.AddUserGroupCombobox.DataSource = emailRecipientsUserList;
// Confirure the combobox to the show the 'Value' portion ONLY from the KeyValuePair
// value set found in the 'emailRecipientsUserList'.
this.AddUserGroupCombobox.DisplayMember = "Value";
// Configure the combobox to utilise the Key from the 'emailRecipientsUserList' as its member value.
this.AddUserGroupCombobox.ValueMember = "Key";
// Set the combobox to owner draw mode - otherwise you cannot change the output style to your own format.
AddUserGroupCombobox.DrawMode = DrawMode.OwnerDrawFixed;
// Instruct the combobox to draw itself using the 'AddUserGroupCombobox_DrawItem' method below.
AddUserGroupCombobox.DrawItem += AddUserGroupCombobox_DrawItem;
// Set the default height for each of the items displayed in the combobox.
AddUserGroupCombobox.ItemHeight = 20;
}
// Mouse index used to reference the position of the cursor when navigating up and down the combobox list.
private readonly int _MouseIndex = -1;
/// <summary>
/// This method is used to draw the items from the 'emailRecipientsUserList' into the combobox,
/// using an owner draw custom format so we can show the the User Group & User
/// Account icons adjacent their relevant names in the combobox list.
///
/// In the method above, we created the 'emailRecipientsUserList' that contains data columns
/// from two different data tables, the first datatable holds the names of the User Groups and the second
/// holds the User Accounts. We're utilizing the KeyValuePair in order to provide a
/// means of applying some logic to the population of our combobox in order to differentiate
/// between a User Group and a User Account. This allows us to dynamically
/// assign the relevant icon display, adjacent each of the items in the combobox list.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void AddUserGroupCombobox_DrawItem(object sender, DrawItemEventArgs e)
{
// Set the textBrush color to Windows Text.
Brush textBrush = SystemBrushes.WindowText;
if (e.Index > -1)
{
// Highlight the combobox item when the mouse cursor hovers over the item in the dropdown list.
if (e.Index == _MouseIndex)
{
e.Graphics.FillRectangle(SystemBrushes.HotTrack, e.Bounds);
textBrush = SystemBrushes.HighlightText;
}
else
{
// Highlight the combobox item when slected in the dropdown list.
if ((e.State & DrawItemState.Selected) == DrawItemState.Selected)
{
e.Graphics.FillRectangle(SystemBrushes.Highlight, e.Bounds);
textBrush = SystemBrushes.HighlightText;
}
else
{
// Restore background colour to deafult when the mouse leaves the item.
e.Graphics.FillRectangle(SystemBrushes.Window, e.Bounds);
}
}
// Draw the string i.e populate the combobox with the list of the text names
// for the User groups & User Accounts
e.Graphics.DrawString(emailRecipientsUserList[e.Index].Value.ToString(), e.Font, textBrush, e.Bounds.Left + 20, e.Bounds.Top);
// IF Statements below are used to determine which icon to display in the drop down list, depending on
// whether the comboxo item is a User Group or User Account name.
if (emailRecipientsUserList[e.Index].Key == "UserGroup")
{
// Image list index '0' represents the icon image for the User Group.
e.Graphics.DrawImage(imageListEmailRecipients.Images[0], e.Bounds.Left, e.Bounds.Top);
}
if (emailRecipientsUserList[e.Index].Key == "Username")
{
// Image list index '0' represents the icon image for the User Account.
e.Graphics.DrawImage(imageListEmailRecipients.Images[1], e.Bounds.Left, e.Bounds.Top);
}
}
}
在您的图像中，它在选择框中显示了图像和文本，当我完成此操作后，我得到了图像和文本列表，但是一旦选择，只有文本显示在框中，我是不是错过了什么。
我已经解决了更改ComboBox.DropDownStyle = ComboBoxStyle.DropDownList
这解决了问题。