Operator '&' cannot be applied to operands of type 'string' and 'string' - CS0019

Operator '&' cannot be applied to operands of type 'string' and 'string' - CS0019

MessageBox.Show("Hello " & "World");

should be

MessageBox.Show("Hello " + "World");

Try stringbuilder also

Avoiding Temporary Strings in C# / Reduce Unnecessary Garbage Collection in C#

Appending strings to existing will produce garbage collection overhead for the program. Instead use Append method of StringBuilder class or Concat, Join methods of String class

The following code differentiates between both :

private void stringbuilder_example()

{

// Appending String - Garbage Collection - Immutable

string CompleteAddress = "";

CompleteAddress += "105, Annanagar ";

CompleteAddress += "Chennai ";

CompleteAddress += "Tamil Nadu ";

MessageBox.Show(CompleteAddress);

// Appending String - using String Builder

System.Text.StringBuilder CompleteAddress1 = new

System.Text.StringBuilder();

CompleteAddress1.Append( "105, Annanagar ");

CompleteAddress1.Append( "Chennai ");

CompleteAddress1.Append( "Tamil Nadu ");

// Error Code

//MessageBox.Show(CompleteAddress1);

// corrected Code

MessageBox.Show(CompleteAddress1.ToString() );

}

C# StringBuilder Class, C# StringBuilder Class Append Method, Appending Strings without Garbage Overhead, Avoiding Temporary Strings in C#, Reduce Unnecessary Garbage Collection in C#

Argument '1': cannot convert from 'System.Text.StringBuilder' to 'string'

Use ‘ToString’ to convert the StringBuilder to String

// Appending String - using String Builder

System.Text.StringBuilder CompleteAddress1 = new

System.Text.StringBuilder();

CompleteAddress1.Append( "105, Annanagar ");

CompleteAddress1.Append( "Chennai ");

CompleteAddress1.Append( "Tamil Nadu ");

// Error Code

//MessageBox.Show(CompleteAddress1);

// corrected Code

MessageBox.Show(CompleteAddress1.ToString() );

Argument '1': cannot convert from 'System.Text.StringBuilder' to 'string' Error