无法将字符串转换为int。错误信息：输入字符串的不正确的格式

Question

我有应该输出fee_paid_int为'20'和total_student_int为'30'怎么过我收到以下错误下面的C＃代码时，我调试的代码int fee_paid_int = Convert.ToInt32(fee_paid_string.Trim());

System.FormatException: Input string was not in a correct format. 

C＃

//Total Student's - Not counting Graduated, Withdrawn or Temporarily Withdrawn 
DataView t_stu = (DataView)total_students_count.Select(DataSourceSelectArguments.Empty); 
    foreach (DataRowView t_stu_sql in t_stu) 
    { 
     total_students_count_label.Text = "Total Current Students: <b>" + t_stu_sql["total_students"].ToString() + "</b><p></p>"; 
    } 

// Total Fee's Paid to Date 
DataView f_paid = (DataView)fees_paid_count.Select(DataSourceSelectArguments.Empty); 
    foreach (DataRowView fee_paid_sql in f_paid) 
    { 
     fees_paid_count_label.Text = "Total Fee's Paid to date: <b>" + fee_paid_sql["fee_paid"].ToString() + "</b><p></p>"; 
    } 

int fee_paid_int = Convert.ToInt32(total_students_count_label.Text.Trim()); 
int total_student_int = Convert.ToInt32(fees_paid_count_label.Text.Trim()); 
int fee_paid_percent = (int)Math.Round((double)(100 * fee_paid_int)/total_student_int); 
fee_paid_percent_label.Text = "Total Percent of Student's who have fully paid their Tution Fee to date " + fee_paid_percent + "%"; 

int fee_paid_percent应该等于66.66，任何帮助，将不胜感激。

Answer 1

total_students_count_label.Text = "Total Current Students: <b>" + 
t_stu_sql["total_students"].ToString() + "</b><p></p>"; 

此控件的内容不能被转换成int，因为这包含非数字和非整数内容..

您可能需要修改这个改变total_students_count_label.Text遏制只有数字 - 在你的情况......它应该是

total_students_count_label.Text = t_stu_sql["total_students"].ToString(); 

Answer 2

在您的代码中替换下面的行。

//Total Student's - Not counting Graduated, Withdrawn or Temporarily Withdrawn 
DataView t_stu = (DataView)total_students_count.Select(DataSourceSelectArguments.Empty); 
foreach (DataRowView t_stu_sql in t_stu) 
{ 
    total_students_count_label.Text = t_stu_sql["total_students"].ToString(); 
} 

    // Total Fee's Paid to Date 
DataView f_paid = (DataView)fees_paid_count.Select(DataSourceSelectArguments.Empty); 
foreach (DataRowView fee_paid_sql in f_paid) 
{ 
    fees_paid_count_label.Text = fee_paid_sql["fee_paid"].ToString(); 
} 

int fee_paid_int = Convert.ToInt32(total_students_count_label.Text.Trim()); 
int total_student_int = Convert.ToInt32(fees_paid_count_label.Text.Trim()); 
int fee_paid_percent = (int)Math.Round((double)(100 * fee_paid_int)/ total_student_int); 
fee_paid_percent_label.Text = "Total Percent of Student's who have fully paid their Tution Fee to date " + fee_paid_percent + "%";