尝试使用此

try this

//Include Header File
Using System.Data.SqlClient;

//Declare 
SqlConnection Con;
SqlCommand Cmd;


Con = new SqlConnection("ConnectionString");
Con.Open();
Cmd = new SqlCommand("Update TableName set Password=@Password where Id= 1",Con);
cmd.parameters.AddwithValue("@Password",TextBox1.text);
Cmd.ExecuteNoQuery();

Con.Close()

尝试:

string command ="UPDATE password SET main_password ='"+ TextBox.Text +"' WHERE id = 1"

顺便说一句，这是对您所做错误的更正.因此，我建议您使用参数化查询来避免问题和SQL注入.

BTW, this was the correction of what you were doing wrong. As such, I would suggest you to use parametrized query to avoid issues and SQL injection.

从
更改sql字符串

Change sql string from

string command ="UPDATE password SET main_password = TextBox.Text WHERE id = 1"

致

To

string command ="UPDATE password SET main_password = ''" + TextBox.Text + "'' WHERE id = 1"

但是使用SqlParameter更好.

But it is way better to use SqlParameter.