Asserting that 1982 "will be a good Democratic year," former president Jimmy Carter last night called on his party to offer a positive program to the nation, in which he said millions are suffering economic hardship unknown since the Great Depression as a result of "ill-advised" actions by the Reagan administration.

Carter, speaking at a party fund-raising dinner during only his third visit here since he left office, told an enthusiastic audience of 1,300 that while he is no longer interested in public offic, "people will recognize that they made a serious mistake in 1980" when they chose Ronald Reagan as their president.

While referring to a national economic crisis, and declaring that "ill-advised actions of last year" have on Democrats to shun "nagative divisive political attacks."

Rather than such partisan rhetoric, the former chief executive said, "what the country wants to see is our country bound together. We can do this not by confrontation but by presenting a positive program.""

The remarks came during a 10-minute talk at a $25-a-plate dinner-dance held at the Indian Spring Country Club in Silver Spring to raise money for the Montgomery County Democratic Central Committee.

The former president received three standing ovations from the audience, which included Maryland Gov. Harry Hughes, Sen. Paul Sarbanes (D-Md.) and many Democratic political figures from Montgomery and Prince George's counties and the District.

During his evening here, the former president also heaped praise upon Patricia Roberts Harris, who served in two Cabinet posts during his administration and now is seeking the Democratic nomination for mayor of the District.

Responding to a reporter's question, Carter described Harris as a "superb administrator" who "can make order out of chaos," and said that if he had "the most difficult job anywhere to give to someone," he would give it to her.

Carter, who has been relatively silent on political issues since leaving office, appeared yesterday largely to be heeding his own advice to mute divisive rhetoric.

Rather than attacking administration policies directly, Carter chose to express what he said were the concerns of the American people.

"I can tell you that the people are desperately concerned about the economic crisis this country faces," he said.

And in outlining a trip abroad he said he would begin today, Carter said he plans to speak at town hall-style meetings in foreign capitals, where he said he was "sure that the people of those nations will be asking the same questions that many people in the United States are asking:

"What will the United States do as the leader of the world to control nuclear weapons? Will we finally be able to ratify the SALT II treaty? Will we move forward in SALT III and subsequent negotiations to slash dramatically the nuclear arsenal of the world?

"Can we hold together the ancient commitments we have made as the majority party in our country . . . insisting on jobs for the unemployed and support for the needy, the aged, the working poor . . . and will our nation protect the rights of the oppressed throughout the world and pursue civil rights? . . .

In explaining his belief this would be "a good Democratic year," Carter said, without referring to the Reagan administration by name, "the errors we've seen so far are now vivid in the public mind."

Carter said he had just given his publisher the completed version of his memoirs, which he had been working on in Georgia since he left Washington.

Concentration on his writing was one reason advanced at the dinner by a friend of Carter's for his relative silence on public issues. Speaking in a humorous vein during his talk, he said another reason was that he had decided to "make my major speeches in the states that had good judgment in 1980," an apparent reference to the fact that Maryland was one of the few states he carried in 1980.

The evening seemed filled with both enthusiasm and nostalgia. Rep. Steny Hoyer of Prince George's appeared to sum up the feelings of many: "I think the turnout tonight demonstrates that we appreciate what he's done. I think people are saying that you've had a rough year like we all did . . .and that things were not as bad as we thought.