頁面上兩個TextBox輸入完按Enter觸發不同的按紐

this.TextBox1.Attributes.Add("onkeypress", "if( event.keyCode == 13 ) {" + this.ClientScript.GetPostBackEventReference(this.Button1, "") + "}");
this.TextBox2.Attributes.Add("onkeypress", "if( event.keyCode == 13 ) {" + this.ClientScript.GetPostBackEventReference(this.Button2 , "") + "}"); 

Me.TextBox1.Attributes.Add("onkeypress", "if( event.keyCode == 13 ) {" & Me.ClientScript.GetPostBackEventReference(Me.Button1, "") & "}")
Me.TextBox2.Attributes.Add("onkeypress", "if( event.keyCode == 13 ) {" & Me.ClientScript.GetPostBackEventReference(Me.Button2, "") & "}")