asked on

C#: populate combobox with data (key:value) from an XML file.

I want to populate a combobox on a windows form with data from an XML file.

how to?
not much documentation, and I also searched past questions but no luck... all questions are in VB.net and/or more complex scenarios than what I need...

thanks!

it_saige

Without seeing your dataset; something like this?

Form1.cs -

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Xml.Linq;

namespace EE_Q28708964
{
	public partial class Form1 : Form
	{
		readonly List<KeyValuePair<int, string>> pairs = new List<KeyValuePair<int, string>>();

		public Form1()
		{
			InitializeComponent();
		}

		private void OnLoad(object sender, EventArgs e)
		{
			XElement element = null;
			try
			{
				element = XElement.Load("DataFile.xml");
				pairs.AddRange((from elem in element.Descendants("pair") select new KeyValuePair<int, string>(elem.Attribute("key").GetAsInteger(), elem.Attribute("value").GetAsString())));
			}
			catch (Exception ex) 
			{ 
				Console.WriteLine(ex);
			}
			comboBox1.DataSource = pairs;
			comboBox1.ValueMember = "Key";
			comboBox1.DisplayMember = "Value";
		}
	}

	static class Extensions
	{
		public static int GetAsInteger(this XAttribute attribute)
		{
			int temp = -1;
			return (attribute != null && !int.TryParse(attribute.Value, out temp)) ? temp : -1;
		}

		public static string GetAsString(this XAttribute attribute)
		{
			return (attribute != null && !string.IsNullOrEmpty(attribute.Value)) ? attribute.Value : string.Empty;
		}
	}
}

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Form1.Designer.cs -

namespace EE_Q28708964
{
	partial class Form1
	{
		/// <summary>
		/// Required designer variable.
		/// </summary>
		private System.ComponentModel.IContainer components = null;

		/// <summary>
		/// Clean up any resources being used.
		/// </summary>
		/// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
		protected override void Dispose(bool disposing)
		{
			if (disposing && (components != null))
			{
				components.Dispose();
			}
			base.Dispose(disposing);
		}

		#region Windows Form Designer generated code

		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{
			this.comboBox1 = new System.Windows.Forms.ComboBox();
			this.SuspendLayout();
			// 
			// comboBox1
			// 
			this.comboBox1.FormattingEnabled = true;
			this.comboBox1.Location = new System.Drawing.Point(12, 12);
			this.comboBox1.Name = "comboBox1";
			this.comboBox1.Size = new System.Drawing.Size(260, 21);
			this.comboBox1.TabIndex = 0;
			// 
			// Form1
			// 
			this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
			this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
			this.ClientSize = new System.Drawing.Size(284, 261);
			this.Controls.Add(this.comboBox1);
			this.Name = "Form1";
			this.Text = "Form1";
			this.Load += new System.EventHandler(this.OnLoad);
			this.ResumeLayout(false);

		}

		#endregion

		private System.Windows.Forms.ComboBox comboBox1;
	}
}

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DataFile.xml (with the 'Copy to Output Directory' property set to 'Copy Always')-

<?xml version="1.0" encoding="utf-8" ?>
<pairs>
	<pair key ="1" value="ONE" />
	<pair key ="2" value="TWO" />
	<pair key ="3" value="THREE" />
	<pair key ="4" value="FOUR" />
	<pair key ="5" value="FIVE" />
	<pair key ="6" value="SIX" />
	<pair key ="7" value="SEVEN" />
	<pair key ="8" value="EIGHT" />
	<pair key ="9" value="NINE" />
	<pair key ="10" value="TEN" />
</pairs>

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Produces the following output -

-saige-

zorba111

ASKER

Thanks saige....

Woah, some pretty complex stuff there for me!

my dataset:

<?xml version="1.0" encoding="Windows-1252"?><JobCategories><JobCategories><JobCatID>8</JobCatID><JobCategory>Accountancy &amp; Finance</JobCategory></JobCategories><JobCategories><JobCatID>20</JobCatID><JobCategory>Banking, Financial services &amp; Insurance</JobCategory></JobCategories><JobCategories><JobCatID>11</JobCatID><JobCategory>Beauty,Hair Care,Leisure &amp; Sport</JobCategory></JobCategories><JobCategories><JobCatID>9</JobCatID><JobCategory>Construction, Architecture &amp; Property</JobCategory></JobCategories><JobCategories><JobCatID>23</JobCatID><JobCategory>Customer Service, Call Centres &amp; Languages</JobCategory></JobCategories><JobCategories><JobCatID>13</JobCatID><JobCategory>Education, Childcare &amp; Training</JobCategory></JobCategories><JobCategories><JobCatID>6</JobCatID><JobCategory>Engineering &amp; Utilities</JobCategory></JobCategories><JobCategories><JobCatID>2</JobCatID><JobCategory>Environmental, Health &amp; Safety</JobCategory></JobCategories><JobCategories><JobCatID>27</JobCatID><JobCategory>General Management</JobCategory></JobCategories><JobCategories><JobCatID>1</JobCatID><JobCategory>Hotel &amp; Catering</JobCategory></JobCategories><JobCategories><JobCatID>16</JobCatID><JobCategory>HR &amp; Recruitment</JobCategory></JobCategories><JobCategories><JobCatID>3</JobCatID><JobCategory>IT</JobCategory></JobCategories><JobCategories><JobCatID>4</JobCatID><JobCategory>Legal</JobCategory></JobCategories><JobCategories><JobCatID>21</JobCatID><JobCategory>Marketing</JobCategory></JobCategories><JobCategories><JobCatID>17</JobCatID><JobCategory>Nursing, Healthcare &amp; Medical</JobCategory></JobCategories><JobCategories><JobCatID>7</JobCatID><JobCategory>Production, Manufacturing &amp; Materials</JobCategory></JobCategories><JobCategories><JobCatID>115</JobCatID><JobCategory>Public Sector</JobCategory></JobCategories><JobCategories><JobCatID>25</JobCatID><JobCategory>Publishing, Media &amp; Creative Arts</JobCategory></JobCategories><JobCategories><JobCatID>10</JobCatID><JobCategory>Retailing, Wholesaling &amp; Purchasing</JobCategory></JobCategories><JobCategories><JobCatID>24</JobCatID><JobCategory>Sales</JobCategory></JobCategories><JobCategories><JobCatID>26</JobCatID><JobCategory>Science, Pharmaceutical &amp; Food</JobCategory></JobCategories><JobCategories><JobCatID>114</JobCatID><JobCategory>Secretarial &amp; Admin</JobCategory></JobCategories><JobCategories><JobCatID>14</JobCatID><JobCategory>Security, Trades &amp; General Services</JobCategory></JobCategories><JobCategories><JobCatID>12</JobCatID><JobCategory>Social &amp; Not for Profit</JobCategory></JobCategories><JobCategories><JobCatID>5</JobCatID><JobCategory>Telecoms</JobCategory></JobCategories><JobCategories><JobCatID>19</JobCatID><JobCategory>Tourism, Travel &amp; Airlines</JobCategory></JobCategories><JobCategories><JobCatID>18</JobCatID><JobCategory>Transport, Warehousing &amp; Motor</JobCategory></JobCategories><JobCategories><JobCatID>28</JobCatID><JobCategory>Graduate</JobCategory></JobCategories><JobCategories><JobCatID>29</JobCatID><JobCategory>Executive</JobCategory></JobCategories><JobCategories><JobCatID>116</JobCatID><JobCategory>Motoring</JobCategory></JobCategories></JobCategories>

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sorry about formatting...

code I tried so far:

            XmlDocument xmldocCategories = new XmlDocument();
            xmldocCategories.Load("JobCategories.xml");

            DataSet dsCategories = new DataSet();
            dsCategories.ReadXml("JobCategories.xml");

            //dsCategories.

            cboCategories.DataSource = dsCategories.Tables[0];
            //cboCategories.DataBind();

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(this was in the form's "Load" event-handler)

and the output:

it_saige

You were very close, the only thing you forgot was specifying your DisplayMember and ValueMember; e.g. -

Form1.cs -

using System;
using System.Data;
using System.Windows.Forms;

namespace EE_Q28708964
{
	public partial class Form1 : Form
	{
		public Form1()
		{
			InitializeComponent();
		}

		private void Form1_Load(object sender, EventArgs e)
		{
			DataSet dsCategories = new DataSet();
			dsCategories.ReadXml("JobCategories.xml");
			cboCategories.DataSource = dsCategories.Tables[0];
			cboCategories.DisplayMember = "JobCategory";
			cboCategories.ValueMember = "JobCatID";
		}
	}
}

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Form1.Designer.cs -

namespace EE_Q28708964
{
	partial class Form1
	{
		/// <summary>
		/// Required designer variable.
		/// </summary>
		private System.ComponentModel.IContainer components = null;

		/// <summary>
		/// Clean up any resources being used.
		/// </summary>
		/// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
		protected override void Dispose(bool disposing)
		{
			if (disposing && (components != null))
			{
				components.Dispose();
			}
			base.Dispose(disposing);
		}

		#region Windows Form Designer generated code

		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{
			this.cboCategories = new System.Windows.Forms.ComboBox();
			this.SuspendLayout();
			// 
			// cboCategories
			// 
			this.cboCategories.FormattingEnabled = true;
			this.cboCategories.Location = new System.Drawing.Point(13, 13);
			this.cboCategories.Name = "cboCategories";
			this.cboCategories.Size = new System.Drawing.Size(259, 21);
			this.cboCategories.TabIndex = 0;
			// 
			// Form1
			// 
			this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
			this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
			this.ClientSize = new System.Drawing.Size(284, 261);
			this.Controls.Add(this.cboCategories);
			this.Name = "Form1";
			this.Text = "Form1";
			this.Load += new System.EventHandler(this.Form1_Load);
			this.ResumeLayout(false);

		}

		#endregion

		private System.Windows.Forms.ComboBox cboCategories;
	}
}

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JobCategories.xml (with the 'Copy to Output Directory' property set to 'Copy Always') -

<?xml version="1.0" encoding="Windows-1252"?>
<JobCategories>
	<JobCategories>
		<JobCatID>8</JobCatID>
		<JobCategory>Accountancy &amp; Finance</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>20</JobCatID>
		<JobCategory>Banking, Financial services &amp; Insurance</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>11</JobCatID>
		<JobCategory>Beauty,Hair Care,Leisure &amp; Sport</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>9</JobCatID>
		<JobCategory>Construction, Architecture &amp; Property</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>23</JobCatID>
		<JobCategory>Customer Service, Call Centres &amp; Languages</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>13</JobCatID>
		<JobCategory>Education, Childcare &amp; Training</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>6</JobCatID>
		<JobCategory>Engineering &amp; Utilities</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>2</JobCatID>
		<JobCategory>Environmental, Health &amp; Safety</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>27</JobCatID>
		<JobCategory>General Management</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>1</JobCatID>
		<JobCategory>Hotel &amp; Catering</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>16</JobCatID>
		<JobCategory>HR &amp; Recruitment</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>3</JobCatID>
		<JobCategory>IT</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>4</JobCatID>
		<JobCategory>Legal</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>21</JobCatID>
		<JobCategory>Marketing</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>17</JobCatID>
		<JobCategory>Nursing, Healthcare &amp; Medical</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>7</JobCatID>
		<JobCategory>Production, Manufacturing &amp; Materials</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>115</JobCatID>
		<JobCategory>Public Sector</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>25</JobCatID>
		<JobCategory>Publishing, Media &amp; Creative Arts</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>10</JobCatID>
		<JobCategory>Retailing, Wholesaling &amp; Purchasing</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>24</JobCatID>
		<JobCategory>Sales</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>26</JobCatID>
		<JobCategory>Science, Pharmaceutical &amp; Food</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>114</JobCatID>
		<JobCategory>Secretarial &amp; Admin</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>14</JobCatID>
		<JobCategory>Security, Trades &amp; General Services</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>12</JobCatID>
		<JobCategory>Social &amp; Not for Profit</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>5</JobCatID>
		<JobCategory>Telecoms</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>19</JobCatID>
		<JobCategory>Tourism, Travel &amp; Airlines</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>18</JobCatID>
		<JobCategory>Transport, Warehousing &amp; Motor</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>28</JobCatID>
		<JobCategory>Graduate</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>29</JobCatID>
		<JobCategory>Executive</JobCategory>
	</JobCategories>
	<JobCategories>
		<JobCatID>116</JobCatID>
		<JobCategory>Motoring</JobCategory>
	</JobCategories>
</JobCategories>

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Which produces the following output -

-saige-

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it_saige

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zorba111

ASKER

Hi Saige,

So I compared your Form1.Designer.cs with mine and came to the conclusion that there is nothing you added in here, its all generated code (correct?).

Next, I was concerned because my XML format was so different from yours. So I added these lines to check if my XML was being parsed into the DataSet correctly:

            String sColumnName = dsCategories.Tables[0].Columns[0].ColumnName;
            sColumnName = dsCategories.Tables[0].Columns[1].ColumnName;

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So those diagnostic lines showed me the XML was being parsed okay. So it was probably about display in the Combo Box. So I looked into those 2x combo box properties you were setting....

I added these two lines, for key and value, *after* assigning the DataSource:

            cboCategories.DataSource = dsCategories.Tables[0];
            cboCategories.ValueMember = dsCategories.Tables[0].Columns[0].ToString();
            cboCategories.DisplayMember = dsCategories.Tables[0].Columns[1].ToString();

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This did the trick, it was more to do with setting the ComboBox than correcting anything to do with XML parsing (as I first thought)...

thanks!

zorba111

ASKER

Sorry, I didn't see your updated answer till now! (not the first time had problems with EE page updates...)

Ok, thanks, and the sort bit is useful too.
many thanks!!