Generally in c# strings were concatinated with symbol '+'
1)'+'
string myName;
myName='GVK' + 'kishore';
2)Append
If it is StringBuilder then we can join as below
StringBuilderObject.Append('GVK');
StringBuilderObject.Append('kishore');
3)Join
Join takes a String array and a separator string and 
produces a single string with one separator between each 
element in the array.Split does the opposite, splitting a 
string made up of several elements separated by a 
separator. 
Ex. string commatext = "alpha,bravo,charlie";
    string[] words = commatext.Split(',');
    string dashed = string.Join("---", words);
    MessageBox.Show(dashed);

Hope helpfull...KishoreG