Code

   public partial class Form1 :  Form
    {
         publicForm1()
         {
            InitializeComponent();
         }
         ColorDialog cd= new ColorDialog();//creating the instance of ColorDialog 
         intflag=0;//creating int variable 
        privatevoidForm1_Load(objectsender, EventArgse)
         {
           
            XmlReaderSettingssetting= new XmlReaderSettings();//creating object of xmlReaderSetting class it will read xml file
            setting.IgnoreWhitespace= true;//ignoring whit space in xml file
            using (XmlReaderreader=XmlReader.Create("D:\\Sachindra\\ColorChange\\ColorChange\\bin\\Debug\\ColorChange.xml", setting))//providing path where xml file is save
            {
                 while (reader.Read())//loop executing
                {
                     if (reader.NodeType==XmlNodeType.Element&& reader.Name=="txtBox1BackColor")//checking condition
                    {
 
                         stringstrCmb1= reader.ReadElementString();//storing value of txtBox1BackColor element(backcolor) in string variable
                         txtBox1.BackColor=System.Drawing.ColorTranslator.FromHtml(strCmb1);//converting string value  into color and changing backcolor of textbox
                    }
                     if (reader.NodeType==XmlNodeType.Element&& reader.Name=="txtBox1ForeColor")//checking condition
                    {
 
                         stringstrCmb1= reader.ReadElementString();//storing value of txtBox1BackColor element (backcolor) in string variable
                         txtBox1.ForeColor=System.Drawing.ColorTranslator.FromHtml(strCmb1);//converting string value  into color and changing forecolor of textbox
                       
                    }
                     if (reader.NodeType==XmlNodeType.Element&& reader.Name=="txtBox2BackColor")//checking condition
                    {
 
                         stringstrCmb1= reader.ReadElementString();//storing value of txtBox2BackColor element(backcolor) in string variable
                         txtBox2.BackColor=System.Drawing.ColorTranslator.FromHtml(strCmb1);//converting string value  into color and changing backcolor of textbox
                      
                    }
                     if (reader.NodeType==XmlNodeType.Element&& reader.Name=="txtBox2ForeColor")//checking condition
                    {
 
                         stringstrCmb1= reader.ReadElementString();//storing value of txtBox2ForeColor element in string variable
                         txtBox2.ForeColor=System.Drawing.ColorTranslator.FromHtml(strCmb1);//converting string value  into color and changing backcolor of textbox
                  
                    }
                     if (reader.NodeType==XmlNodeType.Element&& reader.Name=="txtBox3BackColor")//checking condition
                    {
 
                         stringstrCmb1= reader.ReadElementString();//storing value of txtBox3BackColor element in string variable
                         txtBox3.BackColor=System.Drawing.ColorTranslator.FromHtml(strCmb1);//converting string value  into color and changing backcolor of textbox
                     
                    }
                     if (reader.NodeType==XmlNodeType.Element&& reader.Name=="txtBox3ForeColor")//checking condition
                    {
 
                         stringstrCmb1= reader.ReadElementString();//storing value of txtBox3ForeColor element in string variable
                         txtBox3.ForeColor=System.Drawing.ColorTranslator.FromHtml(strCmb1);//converting string value  into color and changing backcolor of textbox
                  
                    }
                }
            }
         }
 
        privatevoid btnColorDialog1_Click(object sender, EventArgse)
         {
            if (flag==0)//checking condition
            {
                 cd.ShowDialog();//it will show color dialog
                 txtBox1.BackColor=cd.Color;//setting backcolor of textbox
            }
            if (flag==1)//checking condtion 
            {
                 cd.ShowDialog();//it will show color dialog
                 txtBox1.ForeColor=cd.Color;//setting forecolor of textbox
                flag =0;//initializing flag from 0
            }
         }
 
        privatevoid txtBox1_MouseCaptureChanged(object sender, EventArgse)
         {
            flag=1;//initializing flag from 1 when txtBox1 get   MouseCapture event will raise
         }
 
        privatevoid btnColorDailog2_Click(object sender, EventArgse)
         {
            if (flag==0)//checking condition
            {
                 cd.ShowDialog();//it will show color dialog
                 txtBox2.BackColor=cd.Color;//setting backcolor of textbox
            }
            if (flag==1)//checking condtion
            {
                 cd.ShowDialog();//it will show color dialog
                 txtBox2.ForeColor=cd.Color;//setting forecolor of textbox
                flag =0;//initializing flag from 0
            }
         }
 
        privatevoid txtBox2_MouseCaptureChanged(object sender, EventArgse)
         {
            flag=1;//initializing flag from 1 when txtBox2 get MouseCapture event will raise
         }
 
        privatevoid btnColorDialog3_Click(object sender, EventArgse)
         {
            if (flag==0)//checking condition
            {
                 cd.ShowDialog();//it will show color dialog
                 txtBox3.BackColor=cd.Color;//setting backcolor of textbox
            }
            if (flag==1)//checking condtion
            {
                 cd.ShowDialog();//it will show color dialog
                 txtBox3.ForeColor=cd.Color;//setting forecolor of textbox
                flag =0;//initializing flag from 0
            }
         } 
        privatevoid txtBox3_MouseCaptureChanged(object sender, EventArgse)
         {
            flag=1;//initializing flag from 1 when txtBox3 get MouseCapture event will raise
         } 
        privatevoidbtn_Click(objectsender, EventArgse)
         {
            XmlWriterSettingssetting= new XmlWriterSettings();//creating object of XmlWriterSettings that write data in xml format
            setting.Indent=true;
            setting.IndentChars= " ";
            setting.NewLineOnAttributes= true;
            using (XmlWriterwrite=XmlWriter.Create("D:\\Sachindra\\ColorChange\\ColorChange\\bin\\Debug\\ColorChange.xml", setting))//passing path and  write storing path where file will be write
            {
                 write.WriteStartElement("Color");//root element
                 write.WriteStartElement("ChangeColor");//element 
                 write.WriteElementString(txtBox1.Name+ "BackColor", System.Drawing.ColorTranslator.ToHtml(txtBox1.BackColor));//writing textbox name and backcolor in xml format
                 write.WriteElementString(txtBox1.Name+ "ForeColor", System.Drawing.ColorTranslator.ToHtml(txtBox1.ForeColor));//writing textbox name and forecolor in xml format
                write.WriteElementString(txtBox2.Name+ "BackColor", System.Drawing.ColorTranslator.ToHtml(txtBox2.BackColor));//writing textbox name and backcolor in xml format
                 write.WriteElementString(txtBox2.Name+ "ForeColor", System.Drawing.ColorTranslator.ToHtml(txtBox2.ForeColor));//writing textbox name and forecolor in xml format
                 write.WriteElementString(txtBox3.Name+ "BackColor", System.Drawing.ColorTranslator.ToHtml(txtBox3.BackColor));//writing textbox name and backcolor in xml format
                 write.WriteElementString(txtBox3.Name+ "ForeColor", System.Drawing.ColorTranslator.ToHtml(txtBox3.ForeColor));//writing textbox name and forecolor in xml format
                 write.WriteEndElement();//closing element
                write.Flush();//flush method use for forcefully to write data
            }
         } 
        privatevoidbutton1_Click(objectsender, EventArgse)
         {
            this.Close();//apllication will be close
         }
    } 

This demonstration showing backcolor and forecolor of texboxes has changed and when we click on save button it will save in XML format.

 After color changes of textboxes XML file will save setting of backcolor and forecolor of textboxes in XML format as shown below:

This is the simple demonstration on "how to read xml and write xml in c#.net".